diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7dbd29b7..95325a18 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -540,10 +540,11 @@ if(WITH_REDUCED_MEM)
     message(STATUS "Configured for reduced memory environment")
 endif()
 
+set(GENERIC_ARCHDIR "arch/generic")
 
 set(ZLIB_ARCH_SRCS)
-set(ZLIB_ARCH_HDRS)
-set(ARCHDIR "arch/generic")
+set(ZLIB_ARCH_HDRS ${GENERIC_ARCHDIR}/generic_features.h)
+
 if(BASEARCH_ARM_FOUND)
     set(ARCHDIR "arch/arm")
 elseif(BASEARCH_PPC_FOUND)
@@ -558,6 +559,7 @@ elseif(BASEARCH_X86_FOUND)
         add_feature_info(SSE2 1 "Support the SSE2 instruction set, using \"${SSE2FLAG}\"")
     endif()
 else()
+    set(ARCHDIR ${GENERIC_ARCHDIR})
     message(STATUS "No optimized architecture: using ${ARCHDIR}")
 endif()
 
diff --git a/arch/arm/arm_features.h b/arch/arm/arm_features.h
index eca078e3..05c23a88 100644
--- a/arch/arm/arm_features.h
+++ b/arch/arm/arm_features.h
@@ -13,4 +13,42 @@ struct arm_cpu_features {
 
 void Z_INTERNAL arm_check_features(struct arm_cpu_features *features);
 
+#ifdef CPU_FEATURES_H_
+
+#ifdef ARM_NEON
+extern uint32_t adler32_neon(uint32_t adler, const uint8_t *buf, size_t len);
+extern uint32_t chunksize_neon(void);
+extern uint8_t* chunkmemset_safe_neon(uint8_t *out, unsigned dist, unsigned len, unsigned left);
+extern void     inflate_fast_neon(PREFIX3(stream) *strm, uint32_t start);
+
+#  ifdef HAVE_BUILTIN_CTZLL
+    extern uint32_t compare256_neon(const uint8_t *src0, const uint8_t *src1);
+#    ifdef DEFLATE_H_
+        extern uint32_t longest_match_neon(deflate_state *const s, Pos cur_match);
+        extern uint32_t longest_match_slow_neon(deflate_state *const s, Pos cur_match);
+#    endif
+#  endif
+#  ifdef DEFLATE_H_
+    extern void slide_hash_neon(deflate_state *s);
+#  endif
+#endif
+
+#ifdef ARM_ACLE
+extern uint32_t crc32_acle(uint32_t crc, const uint8_t *buf, size_t len);
+
+#  ifdef DEFLATE_H_
+    extern void insert_string_acle(deflate_state *const s, const uint32_t str, uint32_t count);
+    extern Pos quick_insert_string_acle(deflate_state *const s, const uint32_t str);
+    extern uint32_t update_hash_acle(deflate_state *const s, uint32_t h, uint32_t val);
+#  endif
+#endif
+
+#ifdef ARM_SIMD
+#  ifdef DEFLATE_H_
+    extern void slide_hash_armv6(deflate_state *s);
+#  endif
+#endif
+
+#endif
+
 #endif /* ARM_H_ */
diff --git a/arch/generic/generic_features.h b/arch/generic/generic_features.h
new file mode 100644
index 00000000..9e523da9
--- /dev/null
+++ b/arch/generic/generic_features.h
@@ -0,0 +1,60 @@
+/* generic_features.h -- generic C implementations for arch-specific features
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ */
+
+#ifndef GENERIC_FEATURES_H_
+#define GENERIC_FEATURES_H_
+
+typedef uint32_t (*adler32_func)(uint32_t adler, const uint8_t *buf, size_t len);
+typedef uint32_t (*compare256_func)(const uint8_t *src0, const uint8_t *src1);
+typedef uint32_t (*crc32_func)(uint32_t crc32, const uint8_t *buf, size_t len);
+
+extern uint32_t adler32_c(uint32_t adler, const uint8_t *buf, size_t len);
+extern uint32_t chunksize_c(void);
+extern uint8_t* chunkmemset_safe_c(uint8_t *out, unsigned dist, unsigned len, unsigned left);
+extern void     inflate_fast_c(PREFIX3(stream) *strm, uint32_t start);
+
+extern uint32_t PREFIX(crc32_braid)(uint32_t crc, const uint8_t *buf, size_t len);
+
+extern uint32_t compare256_c(const uint8_t *src0, const uint8_t *src1);
+#if defined(UNALIGNED_OK) && BYTE_ORDER == LITTLE_ENDIAN
+extern uint32_t compare256_unaligned_16(const uint8_t *src0, const uint8_t *src1);
+#  ifdef HAVE_BUILTIN_CTZ
+    extern uint32_t compare256_unaligned_32(const uint8_t *src0, const uint8_t *src1);
+#  endif
+#  if defined(UNALIGNED64_OK) && defined(HAVE_BUILTIN_CTZLL)
+    extern uint32_t compare256_unaligned_64(const uint8_t *src0, const uint8_t *src1);
+#  endif
+#endif
+
+#ifdef DEFLATE_H_
+typedef void    (*slide_hash_func)(deflate_state *s);
+
+extern void     insert_string_c(deflate_state *const s, const uint32_t str, uint32_t count);
+extern Pos      quick_insert_string_c(deflate_state *const s, const uint32_t str);
+extern void     slide_hash_c(deflate_state *s);
+extern uint32_t update_hash_c(deflate_state *const s, uint32_t h, uint32_t val);
+
+extern uint32_t longest_match_c(deflate_state *const s, Pos cur_match);
+#  if defined(UNALIGNED_OK) && BYTE_ORDER == LITTLE_ENDIAN
+    extern uint32_t longest_match_unaligned_16(deflate_state *const s, Pos cur_match);
+#    ifdef HAVE_BUILTIN_CTZ
+        extern uint32_t longest_match_unaligned_32(deflate_state *const s, Pos cur_match);
+#    endif
+#    if defined(UNALIGNED64_OK) && defined(HAVE_BUILTIN_CTZLL)
+        extern uint32_t longest_match_unaligned_64(deflate_state *const s, Pos cur_match);
+#    endif
+#  endif
+
+extern uint32_t longest_match_slow_c(deflate_state *const s, Pos cur_match);
+#  if defined(UNALIGNED_OK) && BYTE_ORDER == LITTLE_ENDIAN
+    extern uint32_t longest_match_slow_unaligned_16(deflate_state *const s, Pos cur_match);
+    extern uint32_t longest_match_slow_unaligned_32(deflate_state *const s, Pos cur_match);
+#    ifdef UNALIGNED64_OK
+        extern uint32_t longest_match_slow_unaligned_64(deflate_state *const s, Pos cur_match);
+#    endif
+#  endif
+
+#endif
+
+#endif
diff --git a/arch/power/power_features.h b/arch/power/power_features.h
index 9252364c..43287d36 100644
--- a/arch/power/power_features.h
+++ b/arch/power/power_features.h
@@ -15,4 +15,35 @@ struct power_cpu_features {
 
 void Z_INTERNAL power_check_features(struct power_cpu_features *features);
 
+#ifdef CPU_FEATURES_H_
+
+#ifdef PPC_VMX
+extern uint32_t adler32_vmx(uint32_t adler, const uint8_t *buf, size_t len);
+#  ifdef DEFLATE_H_
+    extern void slide_hash_vmx(deflate_state *s);
+#  endif
+#endif
+
+#ifdef POWER8_VSX
+extern uint32_t adler32_power8(uint32_t adler, const uint8_t *buf, size_t len);
+extern uint32_t chunksize_power8(void);
+extern uint8_t* chunkmemset_safe_power8(uint8_t *out, unsigned dist, unsigned len, unsigned left);
+extern uint32_t crc32_power8(uint32_t crc, const uint8_t *buf, size_t len);
+extern void     inflate_fast_power8(PREFIX3(stream) *strm, uint32_t start);
+
+#  ifdef DEFLATE_H_
+    extern void slide_hash_power8(deflate_state *s);
+#  endif
+#endif
+
+#ifdef POWER9
+extern uint32_t compare256_power9(const uint8_t *src0, const uint8_t *src1);
+#  ifdef DEFLATE_H_
+    extern uint32_t longest_match_power9(deflate_state *const s, Pos cur_match);
+    extern uint32_t longest_match_slow_power9(deflate_state *const s, Pos cur_match);
+#  endif
+#endif
+
+#endif
+
 #endif /* POWER_H_ */
diff --git a/arch/riscv/riscv_features.h b/arch/riscv/riscv_features.h
index c76e967c..1aada419 100644
--- a/arch/riscv/riscv_features.h
+++ b/arch/riscv/riscv_features.h
@@ -15,4 +15,22 @@ struct riscv_cpu_features {
 
 void Z_INTERNAL riscv_check_features(struct riscv_cpu_features *features);
 
+#ifdef CPU_FEATURES_H_
+
+#ifdef RISCV_RVV
+extern uint32_t adler32_rvv(uint32_t adler, const uint8_t *buf, size_t len);
+extern uint32_t adler32_fold_copy_rvv(uint32_t adler, uint8_t *dst, const uint8_t *src, size_t len);
+extern uint32_t chunksize_rvv(void);
+extern uint8_t* chunkmemset_safe_rvv(uint8_t *out, unsigned dist, unsigned len, unsigned left);
+extern uint32_t compare256_rvv(const uint8_t *src0, const uint8_t *src1);
+extern void     inflate_fast_rvv(PREFIX3(stream) *strm, uint32_t start);
+#  ifdef DEFLATE_H_
+    extern uint32_t longest_match_rvv(deflate_state *const s, Pos cur_match);
+    extern uint32_t longest_match_slow_rvv(deflate_state *const s, Pos cur_match);
+    extern void slide_hash_rvv(deflate_state *s);
+#  endif
+#endif
+
+#endif
+
 #endif /* RISCV_H_ */
diff --git a/arch/s390/s390_features.h b/arch/s390/s390_features.h
index b8ffef74..db356d01 100644
--- a/arch/s390/s390_features.h
+++ b/arch/s390/s390_features.h
@@ -7,4 +7,12 @@ struct s390_cpu_features {
 
 void Z_INTERNAL s390_check_features(struct s390_cpu_features *features);
 
+#ifdef CPU_FEATURES_H_
+
+#ifdef S390_CRC32_VX
+extern uint32_t crc32_s390_vx(uint32_t crc, const uint8_t *buf, size_t len);
+#endif
+
+#endif
+
 #endif
diff --git a/arch/x86/x86_features.h b/arch/x86/x86_features.h
index 4a36bde8..016914e5 100644
--- a/arch/x86/x86_features.h
+++ b/arch/x86/x86_features.h
@@ -1,7 +1,7 @@
 /* x86_features.h -- check for CPU features
-* Copyright (C) 2013 Intel Corporation Jim Kukunas
-* For conditions of distribution and use, see copyright notice in zlib.h
-*/
+ * Copyright (C) 2013 Intel Corporation Jim Kukunas
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ */
 
 #ifndef X86_FEATURES_H_
 #define X86_FEATURES_H_
@@ -21,4 +21,81 @@ struct x86_cpu_features {
 
 void Z_INTERNAL x86_check_features(struct x86_cpu_features *features);
 
+#ifdef CPU_FEATURES_H_
+
+#include "fallback_builtins.h"
+#include "crc32.h"
+
+#ifdef X86_SSE2
+extern uint32_t chunksize_sse2(void);
+extern uint8_t* chunkmemset_safe_sse2(uint8_t *out, unsigned dist, unsigned len, unsigned left);
+extern void     inflate_fast_sse2(PREFIX3(stream) *strm, uint32_t start);
+
+#  ifdef HAVE_BUILTIN_CTZ
+    extern uint32_t compare256_sse2(const uint8_t *src0, const uint8_t *src1);
+#    ifdef DEFLATE_H_
+        extern uint32_t longest_match_sse2(deflate_state *const s, Pos cur_match);
+        extern uint32_t longest_match_slow_sse2(deflate_state *const s, Pos cur_match);
+        extern void slide_hash_sse2(deflate_state *s);
+#    endif
+#  endif
+#endif
+
+#ifdef X86_SSSE3
+extern uint32_t adler32_ssse3(uint32_t adler, const uint8_t *buf, size_t len);
+extern uint8_t* chunkmemset_safe_ssse3(uint8_t *out, unsigned dist, unsigned len, unsigned left);
+extern void     inflate_fast_ssse3(PREFIX3(stream) *strm, uint32_t start);
+#endif
+
+#ifdef X86_SSE42
+extern uint32_t adler32_fold_copy_sse42(uint32_t adler, uint8_t *dst, const uint8_t *src, size_t len);
+#  ifdef DEFLATE_H_
+    extern void insert_string_sse42(deflate_state *const s, const uint32_t str, uint32_t count);
+    extern Pos quick_insert_string_sse42(deflate_state *const s, const uint32_t str);
+    extern uint32_t update_hash_sse42(deflate_state *const s, uint32_t h, uint32_t val);
+#  endif
+#endif
+
+#ifdef X86_AVX2
+extern uint32_t adler32_avx2(uint32_t adler, const uint8_t *buf, size_t len);
+extern uint32_t adler32_fold_copy_avx2(uint32_t adler, uint8_t *dst, const uint8_t *src, size_t len);
+extern uint32_t chunksize_avx2(void);
+extern uint8_t* chunkmemset_safe_avx2(uint8_t *out, unsigned dist, unsigned len, unsigned left);
+extern void     inflate_fast_avx2(PREFIX3(stream) *strm, uint32_t start);
+
+#  ifdef HAVE_BUILTIN_CTZ
+    extern uint32_t compare256_avx2(const uint8_t *src0, const uint8_t *src1);
+#    ifdef DEFLATE_H_
+        extern uint32_t longest_match_avx2(deflate_state *const s, Pos cur_match);
+        extern uint32_t longest_match_slow_avx2(deflate_state *const s, Pos cur_match);
+        extern void slide_hash_avx2(deflate_state *s);
+#    endif
+#  endif
+#endif
+#ifdef X86_AVX512
+extern uint32_t adler32_avx512(uint32_t adler, const uint8_t *buf, size_t len);
+extern uint32_t adler32_fold_copy_avx512(uint32_t adler, uint8_t *dst, const uint8_t *src, size_t len);
+#endif
+#ifdef X86_AVX512VNNI
+extern uint32_t adler32_avx512_vnni(uint32_t adler, const uint8_t *buf, size_t len);
+extern uint32_t adler32_fold_copy_avx512_vnni(uint32_t adler, uint8_t *dst, const uint8_t *src, size_t len);
+#endif
+
+#ifdef X86_PCLMULQDQ_CRC
+extern uint32_t crc32_fold_pclmulqdq_reset(crc32_fold *crc);
+extern void     crc32_fold_pclmulqdq_copy(crc32_fold *crc, uint8_t *dst, const uint8_t *src, size_t len);
+extern void     crc32_fold_pclmulqdq(crc32_fold *crc, const uint8_t *src, size_t len, uint32_t init_crc);
+extern uint32_t crc32_fold_pclmulqdq_final(crc32_fold *crc);
+extern uint32_t crc32_pclmulqdq(uint32_t crc32, const uint8_t *buf, size_t len);
+#endif
+#ifdef X86_VPCLMULQDQ_CRC
+extern uint32_t crc32_fold_vpclmulqdq_reset(crc32_fold *crc);
+extern void     crc32_fold_vpclmulqdq_copy(crc32_fold *crc, uint8_t *dst, const uint8_t *src, size_t len);
+extern void     crc32_fold_vpclmulqdq(crc32_fold *crc, const uint8_t *src, size_t len, uint32_t init_crc);
+extern uint32_t crc32_fold_vpclmulqdq_final(crc32_fold *crc);
+extern uint32_t crc32_vpclmulqdq(uint32_t crc32, const uint8_t *buf, size_t len);
+#endif
+
+#endif
+
 #endif /* CPU_H_ */
diff --git a/cpu_features.h b/cpu_features.h
index b095d79a..ea37a0be 100644
--- a/cpu_features.h
+++ b/cpu_features.h
@@ -6,11 +6,14 @@
 #ifndef CPU_FEATURES_H_
 #define CPU_FEATURES_H_
 
-#include "crc32.h"
+#ifdef ZLIB_COMPAT
+typedef struct z_stream_s z_stream;
+#else
+typedef struct zng_stream_s zng_stream;
+#endif
 
 #if defined(X86_FEATURES)
 #  include "arch/x86/x86_features.h"
-#  include "fallback_builtins.h"
 #elif defined(ARM_FEATURES)
 #  include "arch/arm/arm_features.h"
 #elif defined(PPC_FEATURES) || defined(POWER_FEATURES)
@@ -21,6 +24,8 @@
 #  include "arch/riscv/riscv_features.h"
 #endif
 
+#include "arch/generic/generic_features.h"
+
 struct cpu_features {
 #if defined(X86_FEATURES)
     struct x86_cpu_features x86;
@@ -39,264 +44,4 @@ struct cpu_features {
 
 extern void cpu_check_features(struct cpu_features *features);
 
-/* adler32 */
-typedef uint32_t (*adler32_func)(uint32_t adler, const uint8_t *buf, size_t len);
-
-extern uint32_t adler32_c(uint32_t adler, const uint8_t *buf, size_t len);
-#ifdef ARM_NEON
-extern uint32_t adler32_neon(uint32_t adler, const uint8_t *buf, size_t len);
-#endif
-#ifdef PPC_VMX
-extern uint32_t adler32_vmx(uint32_t adler, const uint8_t *buf, size_t len);
-#endif
-#ifdef RISCV_RVV
-extern uint32_t adler32_rvv(uint32_t adler, const uint8_t *buf, size_t len);
-#endif
-#ifdef X86_SSSE3
-extern uint32_t adler32_ssse3(uint32_t adler, const uint8_t *buf, size_t len);
-#endif
-#ifdef X86_AVX2
-extern uint32_t adler32_avx2(uint32_t adler, const uint8_t *buf, size_t len);
-#endif
-#ifdef X86_AVX512
-extern uint32_t adler32_avx512(uint32_t adler, const uint8_t *buf, size_t len);
-#endif
-#ifdef X86_AVX512VNNI
-extern uint32_t adler32_avx512_vnni(uint32_t adler, const uint8_t *buf, size_t len);
-#endif
-#ifdef POWER8_VSX
-extern uint32_t adler32_power8(uint32_t adler, const uint8_t *buf, size_t len);
-#endif
-
-/* adler32 folding */
-#ifdef RISCV_RVV
-extern uint32_t adler32_fold_copy_rvv(uint32_t adler, uint8_t *dst, const uint8_t *src, size_t len);
-#endif
-#ifdef X86_SSE42
-extern uint32_t adler32_fold_copy_sse42(uint32_t adler, uint8_t *dst, const uint8_t *src, size_t len);
-#endif
-#ifdef X86_AVX2
-extern uint32_t adler32_fold_copy_avx2(uint32_t adler, uint8_t *dst, const uint8_t *src, size_t len);
-#endif
-#ifdef X86_AVX512
-extern uint32_t adler32_fold_copy_avx512(uint32_t adler, uint8_t *dst, const uint8_t *src, size_t len);
-#endif
-#ifdef X86_AVX512VNNI
-extern uint32_t adler32_fold_copy_avx512_vnni(uint32_t adler, uint8_t *dst, const uint8_t *src, size_t len);
-#endif
-
-/* CRC32 folding */
-#ifdef X86_PCLMULQDQ_CRC
-extern uint32_t crc32_fold_pclmulqdq_reset(crc32_fold *crc);
-extern void     crc32_fold_pclmulqdq_copy(crc32_fold *crc, uint8_t *dst, const uint8_t *src, size_t len);
-extern void     crc32_fold_pclmulqdq(crc32_fold *crc, const uint8_t *src, size_t len, uint32_t init_crc);
-extern uint32_t crc32_fold_pclmulqdq_final(crc32_fold *crc);
-extern uint32_t crc32_pclmulqdq(uint32_t crc32, const uint8_t *buf, size_t len);
-#endif
-#ifdef X86_VPCLMULQDQ_CRC
-extern uint32_t crc32_fold_vpclmulqdq_reset(crc32_fold *crc);
-extern void     crc32_fold_vpclmulqdq_copy(crc32_fold *crc, uint8_t *dst, const uint8_t *src, size_t len);
-extern void     crc32_fold_vpclmulqdq(crc32_fold *crc, const uint8_t *src, size_t len, uint32_t init_crc);
-extern uint32_t crc32_fold_vpclmulqdq_final(crc32_fold *crc);
-extern uint32_t crc32_vpclmulqdq(uint32_t crc32, const uint8_t *buf, size_t len);
-#endif
-
-/* memory chunking */
-extern uint32_t chunksize_c(void);
-extern uint8_t* chunkmemset_safe_c(uint8_t *out, unsigned dist, unsigned len, unsigned left);
-#ifdef X86_SSE2
-extern uint32_t chunksize_sse2(void);
-extern uint8_t* chunkmemset_safe_sse2(uint8_t *out, unsigned dist, unsigned len, unsigned left);
-#endif
-#ifdef X86_SSSE3
-extern uint8_t* chunkmemset_safe_ssse3(uint8_t *out, unsigned dist, unsigned len, unsigned left);
-#endif
-#ifdef X86_AVX2
-extern uint32_t chunksize_avx2(void);
-extern uint8_t* chunkmemset_safe_avx2(uint8_t *out, unsigned dist, unsigned len, unsigned left);
-#endif
-#ifdef ARM_NEON
-extern uint32_t chunksize_neon(void);
-extern uint8_t* chunkmemset_safe_neon(uint8_t *out, unsigned dist, unsigned len, unsigned left);
-#endif
-#ifdef POWER8_VSX
-extern uint32_t chunksize_power8(void);
-extern uint8_t* chunkmemset_safe_power8(uint8_t *out, unsigned dist, unsigned len, unsigned left);
-#endif
-#ifdef RISCV_RVV
-extern uint32_t chunksize_rvv(void);
-extern uint8_t* chunkmemset_safe_rvv(uint8_t *out, unsigned dist, unsigned len, unsigned left);
-#endif
-
-#ifdef ZLIB_COMPAT
-typedef struct z_stream_s z_stream;
-#else
-typedef struct zng_stream_s zng_stream;
-#endif
-
-/* inflate fast loop */
-extern void inflate_fast_c(PREFIX3(stream) *strm, uint32_t start);
-#ifdef X86_SSE2
-extern void inflate_fast_sse2(PREFIX3(stream) *strm, uint32_t start);
-#endif
-#ifdef X86_SSSE3
-extern void inflate_fast_ssse3(PREFIX3(stream) *strm, uint32_t start);
-#endif
-#ifdef X86_AVX2
-extern void inflate_fast_avx2(PREFIX3(stream) *strm, uint32_t start);
-#endif
-#ifdef ARM_NEON
-extern void inflate_fast_neon(PREFIX3(stream) *strm, uint32_t start);
-#endif
-#ifdef POWER8_VSX
-extern void inflate_fast_power8(PREFIX3(stream) *strm, uint32_t start);
-#endif
-#ifdef RISCV_RVV
-extern void inflate_fast_rvv(PREFIX3(stream) *strm, uint32_t start);
-#endif
-
-/* CRC32 */
-typedef uint32_t (*crc32_func)(uint32_t crc32, const uint8_t *buf, size_t len);
-
-extern uint32_t PREFIX(crc32_braid)(uint32_t crc, const uint8_t *buf, size_t len);
-#ifdef ARM_ACLE
-extern uint32_t crc32_acle(uint32_t crc, const uint8_t *buf, size_t len);
-#elif defined(POWER8_VSX)
-extern uint32_t crc32_power8(uint32_t crc, const uint8_t *buf, size_t len);
-#elif defined(S390_CRC32_VX)
-extern uint32_t crc32_s390_vx(uint32_t crc, const uint8_t *buf, size_t len);
-#endif
-
-/* compare256 */
-typedef uint32_t (*compare256_func)(const uint8_t *src0, const uint8_t *src1);
-
-extern uint32_t compare256_c(const uint8_t *src0, const uint8_t *src1);
-#if defined(UNALIGNED_OK) && BYTE_ORDER == LITTLE_ENDIAN
-extern uint32_t compare256_unaligned_16(const uint8_t *src0, const uint8_t *src1);
-#ifdef HAVE_BUILTIN_CTZ
-extern uint32_t compare256_unaligned_32(const uint8_t *src0, const uint8_t *src1);
-#endif
-#if defined(UNALIGNED64_OK) && defined(HAVE_BUILTIN_CTZLL)
-extern uint32_t compare256_unaligned_64(const uint8_t *src0, const uint8_t *src1);
-#endif
-#endif
-#if defined(X86_SSE2) && defined(HAVE_BUILTIN_CTZ)
-extern uint32_t compare256_sse2(const uint8_t *src0, const uint8_t *src1);
-#endif
-#if defined(X86_AVX2) && defined(HAVE_BUILTIN_CTZ)
-extern uint32_t compare256_avx2(const uint8_t *src0, const uint8_t *src1);
-#endif
-#if defined(ARM_NEON) && defined(HAVE_BUILTIN_CTZLL)
-extern uint32_t compare256_neon(const uint8_t *src0, const uint8_t *src1);
-#endif
-#ifdef POWER9
-extern uint32_t compare256_power9(const uint8_t *src0, const uint8_t *src1);
-#endif
-#ifdef RISCV_RVV
-extern uint32_t compare256_rvv(const uint8_t *src0, const uint8_t *src1);
-#endif
-
-#ifdef DEFLATE_H_
-/* insert_string */
-extern void insert_string_c(deflate_state *const s, const uint32_t str, uint32_t count);
-#ifdef X86_SSE42
-extern void insert_string_sse42(deflate_state *const s, const uint32_t str, uint32_t count);
-#elif defined(ARM_ACLE)
-extern void insert_string_acle(deflate_state *const s, const uint32_t str, uint32_t count);
-#endif
-
-/* longest_match */
-extern uint32_t longest_match_c(deflate_state *const s, Pos cur_match);
-#if defined(UNALIGNED_OK) && BYTE_ORDER == LITTLE_ENDIAN
-extern uint32_t longest_match_unaligned_16(deflate_state *const s, Pos cur_match);
-#ifdef HAVE_BUILTIN_CTZ
-extern uint32_t longest_match_unaligned_32(deflate_state *const s, Pos cur_match);
-#endif
-#if defined(UNALIGNED64_OK) && defined(HAVE_BUILTIN_CTZLL)
-extern uint32_t longest_match_unaligned_64(deflate_state *const s, Pos cur_match);
-#endif
-#endif
-#if defined(X86_SSE2) && defined(HAVE_BUILTIN_CTZ)
-extern uint32_t longest_match_sse2(deflate_state *const s, Pos cur_match);
-#endif
-#if defined(X86_AVX2) && defined(HAVE_BUILTIN_CTZ)
-extern uint32_t longest_match_avx2(deflate_state *const s, Pos cur_match);
-#endif
-#if defined(ARM_NEON) && defined(HAVE_BUILTIN_CTZLL)
-extern uint32_t longest_match_neon(deflate_state *const s, Pos cur_match);
-#endif
-#ifdef POWER9
-extern uint32_t longest_match_power9(deflate_state *const s, Pos cur_match);
-#endif
-#ifdef RISCV_RVV
-extern uint32_t longest_match_rvv(deflate_state *const s, Pos cur_match);
-#endif
-
-/* longest_match_slow */
-extern uint32_t longest_match_slow_c(deflate_state *const s, Pos cur_match);
-#if defined(UNALIGNED_OK) && BYTE_ORDER == LITTLE_ENDIAN
-extern uint32_t longest_match_slow_unaligned_16(deflate_state *const s, Pos cur_match);
-extern uint32_t longest_match_slow_unaligned_32(deflate_state *const s, Pos cur_match);
-#ifdef UNALIGNED64_OK
-extern uint32_t longest_match_slow_unaligned_64(deflate_state *const s, Pos cur_match);
-#endif
-#endif
-#if defined(X86_SSE2) && defined(HAVE_BUILTIN_CTZ)
-extern uint32_t longest_match_slow_sse2(deflate_state *const s, Pos cur_match);
-#endif
-#if defined(X86_AVX2) && defined(HAVE_BUILTIN_CTZ)
-extern uint32_t longest_match_slow_avx2(deflate_state *const s, Pos cur_match);
-#endif
-#if defined(ARM_NEON) && defined(HAVE_BUILTIN_CTZLL)
-extern uint32_t longest_match_slow_neon(deflate_state *const s, Pos cur_match);
-#endif
-#ifdef POWER9
-extern uint32_t longest_match_slow_power9(deflate_state *const s, Pos cur_match);
-#endif
-#ifdef RISCV_RVV
-extern uint32_t longest_match_slow_rvv(deflate_state *const s, Pos cur_match);
-#endif
-
-/* quick_insert_string */
-extern Pos quick_insert_string_c(deflate_state *const s, const uint32_t str);
-#ifdef X86_SSE42
-extern Pos quick_insert_string_sse42(deflate_state *const s, const uint32_t str);
-#elif defined(ARM_ACLE)
-extern Pos quick_insert_string_acle(deflate_state *const s, const uint32_t str);
-#endif
-
-/* slide_hash */
-typedef void (*slide_hash_func)(deflate_state *s);
-
-#ifdef X86_SSE2
-extern void slide_hash_sse2(deflate_state *s);
-#endif
-#if defined(ARM_SIMD)
-extern void slide_hash_armv6(deflate_state *s);
-#endif
-#if defined(ARM_NEON)
-extern void slide_hash_neon(deflate_state *s);
-#endif
-#if defined(PPC_VMX)
-extern void slide_hash_vmx(deflate_state *s);
-#endif
-#if defined(POWER8_VSX)
-extern void slide_hash_power8(deflate_state *s);
-#endif
-#if defined(RISCV_RVV)
-extern void slide_hash_rvv(deflate_state *s);
-#endif
-#ifdef X86_AVX2
-extern void slide_hash_avx2(deflate_state *s);
-#endif
-
-/* update_hash */
-extern uint32_t update_hash_c(deflate_state *const s, uint32_t h, uint32_t val);
-#ifdef X86_SSE42
-extern uint32_t update_hash_sse42(deflate_state *const s, uint32_t h, uint32_t val);
-#elif defined(ARM_ACLE)
-extern uint32_t update_hash_acle(deflate_state *const s, uint32_t h, uint32_t val);
-#endif
-#endif
-
 #endif
diff --git a/fallback_builtins.h b/fallback_builtins.h
index 79072a10..8303508f 100644
--- a/fallback_builtins.h
+++ b/fallback_builtins.h
@@ -5,9 +5,6 @@
 #if defined(_M_IX86) || defined(_M_AMD64) || defined(_M_IA64) ||  defined(_M_ARM) || defined(_M_ARM64) || defined(_M_ARM64EC)
 
 #include <intrin.h>
-#ifdef X86_FEATURES
-#  include "arch/x86/x86_features.h"
-#endif
 
 /* This is not a general purpose replacement for __builtin_ctz. The function expects that value is != 0.
  * Because of that assumption trailing_zero is not initialized and the return value is not checked.