Fix visibility issues when compiling with mingw32.

configure.ac

@@ -46,4 +46,14 @@ AC_CONFIG_FILES([
   libbcg729.pc
 ])
 
+case "$target_os" in
+	*mingw*)
+		CFLAGS="$CFLAGS -D_WIN32_WINNT=0x0501"
+	;;
+	*)
+		CFLAGS="$CFLAGS -fvisibility=hidden"
+	;;
+esac
+
+
 AC_OUTPUT

include/bcg729/decoder.h

@@ -23,7 +23,7 @@
 typedef struct bcg729DecoderChannelContextStruct_struct bcg729DecoderChannelContextStruct;
 #include <stdint.h>
 
-#ifdef _MSC_VER
+#ifdef WIN32
 #define BCG729_VISIBILITY
 #else
 #define BCG729_VISIBILITY __attribute__ ((visibility ("default")))

include/bcg729/encoder.h

@@ -23,7 +23,7 @@
 #include <stdint.h>
 typedef struct bcg729EncoderChannelContextStruct_struct bcg729EncoderChannelContextStruct;
 
-#ifdef _MSC_VER
+#ifdef WIN32
 #define BCG729_VISIBILITY
 #else
 #define BCG729_VISIBILITY __attribute__ ((visibility ("default")))

src/Makefile.am

@@ -27,5 +27,3 @@ libbcg729_la_SOURCES=	LP2LSPConversion.c \
 libbcg729_la_LDFLAGS= -no-undefined
 
 INCLUDES= -I$(top_srcdir)/include
-
-AM_CFLAGS=-fvisibility=hidden