Add runtime NEON detection for AArch32

- Add NEON detection w/o libavutil
- Remove libavutil dependency with ARM

CMakeLists.txt

@@ -134,7 +134,7 @@ if (WITH_AVFFT)
   endif ()
 endif ()
 
-if (WITH_AVFFT OR (CMAKE_SYSTEM_PROCESSOR MATCHES "^arm" AND SIMD32_FOUND AND WITH_CR32))
+if (WITH_AVFFT AND (CMAKE_SYSTEM_PROCESSOR MATCHES "^arm" AND SIMD32_FOUND AND WITH_CR32))
   find_package (LibAVUtil)
   if (AVUTIL_FOUND)
     include_directories (${AVUTIL_INCLUDE_DIRS})
@@ -146,6 +146,7 @@ check_function_exists (lrint HAVE_LRINT)
 check_include_files (fenv.h HAVE_FENV_H)
 check_include_files (stdbool.h HAVE_STDBOOL_H)
 check_include_files (stdint.h HAVE_STDINT_H)
+check_include_files (sys/auxv.h HAVE_GETAUXVAL)
 test_big_endian (HAVE_BIGENDIAN)
 
 

msvc/soxr-config.h

@@ -14,6 +14,7 @@
 #define HAVE_FENV_H 1
 #define HAVE_STDBOOL_H 1
 #define HAVE_STDINT_H 1
+#define HAVE_GETAUXVAL 0
 #define HAVE_LRINT 1
 #define HAVE_BIGENDIAN 0
 

soxr-config.h.in

@@ -11,6 +11,7 @@
 #cmakedefine01 HAVE_FENV_H
 #cmakedefine01 HAVE_STDBOOL_H
 #cmakedefine01 HAVE_STDINT_H
+#cmakedefine01 HAVE_GETAUXVAL
 #cmakedefine01 HAVE_LRINT
 #cmakedefine01 HAVE_BIGENDIAN
 

src/soxr.c

@@ -12,6 +12,9 @@
 
 #if AVUTIL_FOUND
   #include <libavutil/cpu.h>
+#elif HAVE_GETAUXVAL && defined(__arm__)
+  #include <sys/auxv.h>
+  #include <asm/hwcap.h>
 #endif
 
 
@@ -256,6 +259,8 @@ soxr_io_spec_t soxr_io_spec(
     return true;
   #elif defined AV_CPU_FLAG_NEON
     return !!(av_get_cpu_flags() & AV_CPU_FLAG_NEON);
+  #elif defined HWCAP_NEON
+    return !!(getauxval(AT_HWCAP) & HWCAP_NEON);
   #else
     return false;
   #endif