fix linux build error

Author: jipeng

ext/image_loader/Makefile.am

@@ -18,5 +18,5 @@ libpsx_image_la_SOURCES = \
 
 libpsx_image_la_LDFLAGS = -no-undefined -release $(VERSION_MAJOR).$(VERSION_MINOR).$(VERSION_MICRO)
 
-libpsx_image_la_LIBADD = -lpicasso -ldl
+libpsx_image_la_LIBADD = ../../src/libpicasso.la -ldl
 

ext/image_loader/gif/gif_module.c

@@ -129,7 +129,7 @@ static int get_gif_delay_time(GifFileType *gif, int frame)
     ExtensionBlock *ext = gif->SavedImages[frame].ExtensionBlocks;
     int len = gif->SavedImages[frame].ExtensionBlockCount;
     for (x = 0; x < len; ++x, ++ext) {
-        if ((ext->Function == GRAPHICS_EXT_FUNC_CODE)) {
+        if (ext->Function == GRAPHICS_EXT_FUNC_CODE) {
             return ((ext->Bytes[2] << 8) | (ext->Bytes[1])) * 10; // ms
         }
     }

ext/image_loader/psx_image_loader.c

@@ -102,7 +102,7 @@ psx_image* PICAPI psx_image_create_from_data(ps_byte* data, ps_color_format fmt,
         return NULL;
     }
 
-    if (fmt < 0 || fmt >= COLOR_FORMAT_UNKNOWN) {
+    if ((int)fmt < 0 || fmt >= COLOR_FORMAT_UNKNOWN) {
         if (err_code)
             *err_code = S_BAD_PARAMS;
         return NULL;