fix hardcoded tables compililation caused by missing math constants

Add -D_XOPEN_SOURCE=600 to host cflags to make the constants in math.h
available. Include math.h where necessary and remove redundant M_PI
defines.

configure

@@ -1682,7 +1682,7 @@ SLIB_INSTALL_LINKS='$(SLIBNAME_WITH_MAJOR) $(SLIBNAME)'
 AS_O='-o $@'
 CC_O='-o $@'
 
-host_cflags='-D_ISOC99_SOURCE -O3 -g'
+host_cflags='-D_ISOC99_SOURCE -D_XOPEN_SOURCE=600 -O3 -g'
 host_libs='-lm'
 
 target_path='$(CURDIR)'

libavcodec/aacps_tablegen.h

@@ -23,6 +23,7 @@
 #ifndef AACPS_TABLEGEN_H
 #define AACPS_TABLEGEN_H
 
+#include <math.h>
 #include <stdint.h>
 
 #if CONFIG_HARDCODED_TABLES

libavcodec/cos_tablegen.c

@@ -24,9 +24,6 @@
 #include <string.h>
 #include <math.h>
 
-#ifndef M_PI
-#define M_PI 3.14159265358979323846
-#endif
 #define BITS 16
 #define FLOATFMT "%.18e"
 #define FIXEDFMT "%6d"

libavcodec/sinewin_tablegen.c

@@ -26,9 +26,6 @@
 #define SINETABLE(size) \
     float ff_sine_##size[size]
 #define FF_ARRAY_ELEMS(a) (sizeof(a) / sizeof((a)[0]))
-#ifndef M_PI
-#define M_PI 3.14159265358979323846
-#endif
 #include "sinewin_tablegen.h"
 #include "tableprint.h"