Define a backup log2f if the compiler doesn't have it

Alc/ALc.c

@@ -1213,9 +1213,6 @@ JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *jvm, void* UNUSED(reserved))
     pthread_setspecific(gJVMThreadKey, env);
     return JNI_VERSION_1_4;
 }
-
-/* Android doesn't have log2f, really? */
-#define log2f(x)  (logf(x) / logf(2.0f))
 #endif
 
 

CMakeLists.txt

@@ -505,6 +505,7 @@ CHECK_SYMBOL_EXISTS(posix_memalign   stdlib.h HAVE_POSIX_MEMALIGN)
 CHECK_SYMBOL_EXISTS(_aligned_malloc  malloc.h HAVE__ALIGNED_MALLOC)
 CHECK_SYMBOL_EXISTS(lrintf math.h HAVE_LRINTF)
 CHECK_SYMBOL_EXISTS(modff  math.h HAVE_MODFF)
+CHECK_SYMBOL_EXISTS(log2f  math.h HAVE_LOG2F)
 IF(NOT HAVE_C99_VLA)
     CHECK_SYMBOL_EXISTS(alloca malloc.h HAVE_ALLOCA)
     IF(NOT HAVE_ALLOCA)

common/math_defs.h

@@ -22,6 +22,13 @@ static const union msvc_inf_hack {
 #define HUGE_VALF (msvc_inf_union.f)
 #endif
 
+#ifndef HAVE_LOG2F
+static inline float log2f(float f)
+{
+    return logf(f) / logf(2.0f);
+}
+#endif
+
 #define DEG2RAD(x)  ((float)(x) * (F_PI/180.0f))
 #define RAD2DEG(x)  ((float)(x) * (180.0f/F_PI))
 

config.h.in

@@ -80,6 +80,9 @@
 /* Define if we have the modff function */
 #cmakedefine HAVE_MODFF
 
+/* Define if we have the log2f function */
+#cmakedefine HAVE_LOG2F
+
 /* Define if we have the strtof function */
 #cmakedefine HAVE_STRTOF