Update external libraries.

extras/dr_flac.h

 /*
 FLAC audio decoder. Choice of public domain or MIT-0. See license statements at the end of this file.
-dr_flac - v0.12.22 - 2020-11-01
+dr_flac - v0.12.23 - 2020-11-21
 
 David Reid - mackron@gmail.com
 
@@ -232,7 +232,7 @@ extern "C" {
 
 #define DRFLAC_VERSION_MAJOR     0
 #define DRFLAC_VERSION_MINOR     12
-#define DRFLAC_VERSION_REVISION  22
+#define DRFLAC_VERSION_REVISION  23
 #define DRFLAC_VERSION_STRING    DRFLAC_XSTRINGIFY(DRFLAC_VERSION_MAJOR) "." DRFLAC_XSTRINGIFY(DRFLAC_VERSION_MINOR) "." DRFLAC_XSTRINGIFY(DRFLAC_VERSION_REVISION)
 
 #include <stddef.h> /* For size_t. */
@@ -1354,6 +1354,8 @@ DRFLAC_API drflac_bool32 drflac_next_cuesheet_track(drflac_cuesheet_track_iterat
     #else
         #define DRFLAC_INLINE inline __attribute__((always_inline))
     #endif
+#elif defined(__WATCOMC__)
+    #define DRFLAC_INLINE __inline
 #else
     #define DRFLAC_INLINE
 #endif
@@ -8356,12 +8358,13 @@ _wfopen() isn't always available in all compilation environments.
     * MSVC seems to support it universally as far back as VC6 from what I can tell (haven't checked further back).
     * MinGW-64 (both 32- and 64-bit) seems to support it.
     * MinGW wraps it in !defined(__STRICT_ANSI__).
+    * OpenWatcom wraps it in !defined(_NO_EXT_KEYS).
 
 This can be reviewed as compatibility issues arise. The preference is to use _wfopen_s() and _wfopen() as opposed to the wcsrtombs()
 fallback, so if you notice your compiler not detecting this properly I'm happy to look at adding support.
 */
 #if defined(_WIN32)
-    #if defined(_MSC_VER) || defined(__MINGW64__) || !defined(__STRICT_ANSI__)
+    #if defined(_MSC_VER) || defined(__MINGW64__) || (!defined(__STRICT_ANSI__) && !defined(_NO_EXT_KEYS))
         #define DRFLAC_HAS_WFOPEN
     #endif
 #endif
@@ -11789,6 +11792,9 @@ DRFLAC_API drflac_bool32 drflac_next_cuesheet_track(drflac_cuesheet_track_iterat
 /*
 REVISION HISTORY
 ================
+v0.12.23 - 2020-11-21
+  - Fix compilation with OpenWatcom.
+
 v0.12.22 - 2020-11-01
   - Fix an error with the previous release.
 

extras/dr_mp3.h

 /*
 MP3 audio decoder. Choice of public domain or MIT-0. See license statements at the end of this file.
-dr_mp3 - v0.6.19 - 2020-11-13
+dr_mp3 - v0.6.20 - 2020-11-21
 
 David Reid - mackron@gmail.com
 
@@ -95,7 +95,7 @@ extern "C" {
 
 #define DRMP3_VERSION_MAJOR     0
 #define DRMP3_VERSION_MINOR     6
-#define DRMP3_VERSION_REVISION  19
+#define DRMP3_VERSION_REVISION  20
 #define DRMP3_VERSION_STRING    DRMP3_XSTRINGIFY(DRMP3_VERSION_MAJOR) "." DRMP3_XSTRINGIFY(DRMP3_VERSION_MINOR) "." DRMP3_XSTRINGIFY(DRMP3_VERSION_REVISION)
 
 #include <stddef.h> /* For size_t. */
@@ -239,6 +239,8 @@ typedef drmp3_int32 drmp3_result;
     #else
         #define DRMP3_INLINE inline __attribute__((always_inline))
     #endif
+#elif defined(__WATCOMC__)
+    #define DRMP3_INLINE __inline
 #else
     #define DRMP3_INLINE
 #endif
@@ -3378,12 +3380,13 @@ _wfopen() isn't always available in all compilation environments.
     * MSVC seems to support it universally as far back as VC6 from what I can tell (haven't checked further back).
     * MinGW-64 (both 32- and 64-bit) seems to support it.
     * MinGW wraps it in !defined(__STRICT_ANSI__).
+    * OpenWatcom wraps it in !defined(_NO_EXT_KEYS).
 
 This can be reviewed as compatibility issues arise. The preference is to use _wfopen_s() and _wfopen() as opposed to the wcsrtombs()
 fallback, so if you notice your compiler not detecting this properly I'm happy to look at adding support.
 */
 #if defined(_WIN32)
-    #if defined(_MSC_VER) || defined(__MINGW64__) || !defined(__STRICT_ANSI__)
+    #if defined(_MSC_VER) || defined(__MINGW64__) || (!defined(__STRICT_ANSI__) && !defined(_NO_EXT_KEYS))
         #define DRMP3_HAS_WFOPEN
     #endif
 #endif
@@ -4435,6 +4438,9 @@ counts rather than sample counts.
 /*
 REVISION HISTORY
 ================
+v0.6.20 - 2020-11-21
+  - Fix compilation with OpenWatcom.
+
 v0.6.19 - 2020-11-13
   - Minor code clean up.
 

extras/dr_wav.h

 /*
 WAV audio loader and writer. Choice of public domain or MIT-0. See license statements at the end of this file.
-dr_wav - v0.12.14 - 2020-11-13
+dr_wav - v0.12.15 - 2020-11-21
 
 David Reid - mackron@gmail.com
 
@@ -144,7 +144,7 @@ extern "C" {
 
 #define DRWAV_VERSION_MAJOR     0
 #define DRWAV_VERSION_MINOR     12
-#define DRWAV_VERSION_REVISION  14
+#define DRWAV_VERSION_REVISION  15
 #define DRWAV_VERSION_STRING    DRWAV_XSTRINGIFY(DRWAV_VERSION_MAJOR) "." DRWAV_XSTRINGIFY(DRWAV_VERSION_MINOR) "." DRWAV_XSTRINGIFY(DRWAV_VERSION_REVISION)
 
 #include <stddef.h> /* For size_t. */
@@ -1021,6 +1021,8 @@ DRWAV_API drwav_bool32 drwav_fourcc_equal(const drwav_uint8* a, const char* b);
     #else
         #define DRWAV_INLINE inline __attribute__((always_inline))
     #endif
+#elif defined(__WATCOMC__)
+    #define DRWAV_INLINE __inline
 #else
     #define DRWAV_INLINE
 #endif
@@ -1097,7 +1099,7 @@ you doing?! (Let me know, I'd be curious!) Second, you can adjust these by #defi
 
 static const drwav_uint8 drwavGUID_W64_RIFF[16] = {0x72,0x69,0x66,0x66, 0x2E,0x91, 0xCF,0x11, 0xA5,0xD6, 0x28,0xDB,0x04,0xC1,0x00,0x00};    /* 66666972-912E-11CF-A5D6-28DB04C10000 */
 static const drwav_uint8 drwavGUID_W64_WAVE[16] = {0x77,0x61,0x76,0x65, 0xF3,0xAC, 0xD3,0x11, 0x8C,0xD1, 0x00,0xC0,0x4F,0x8E,0xDB,0x8A};    /* 65766177-ACF3-11D3-8CD1-00C04F8EDB8A */
-static const drwav_uint8 drwavGUID_W64_JUNK[16] = {0x6A,0x75,0x6E,0x6B, 0xF3,0xAC, 0xD3,0x11, 0x8C,0xD1, 0x00,0xC0,0x4F,0x8E,0xDB,0x8A};    /* 6B6E756A-ACF3-11D3-8CD1-00C04F8EDB8A */
+/*static const drwav_uint8 drwavGUID_W64_JUNK[16] = {0x6A,0x75,0x6E,0x6B, 0xF3,0xAC, 0xD3,0x11, 0x8C,0xD1, 0x00,0xC0,0x4F,0x8E,0xDB,0x8A};*/    /* 6B6E756A-ACF3-11D3-8CD1-00C04F8EDB8A */
 static const drwav_uint8 drwavGUID_W64_FMT [16] = {0x66,0x6D,0x74,0x20, 0xF3,0xAC, 0xD3,0x11, 0x8C,0xD1, 0x00,0xC0,0x4F,0x8E,0xDB,0x8A};    /* 20746D66-ACF3-11D3-8CD1-00C04F8EDB8A */
 static const drwav_uint8 drwavGUID_W64_FACT[16] = {0x66,0x61,0x63,0x74, 0xF3,0xAC, 0xD3,0x11, 0x8C,0xD1, 0x00,0xC0,0x4F,0x8E,0xDB,0x8A};    /* 74636166-ACF3-11D3-8CD1-00C04F8EDB8A */
 static const drwav_uint8 drwavGUID_W64_DATA[16] = {0x64,0x61,0x74,0x61, 0xF3,0xAC, 0xD3,0x11, 0x8C,0xD1, 0x00,0xC0,0x4F,0x8E,0xDB,0x8A};    /* 61746164-ACF3-11D3-8CD1-00C04F8EDB8A */
@@ -3000,12 +3002,13 @@ _wfopen() isn't always available in all compilation environments.
     * MSVC seems to support it universally as far back as VC6 from what I can tell (haven't checked further back).
     * MinGW-64 (both 32- and 64-bit) seems to support it.
     * MinGW wraps it in !defined(__STRICT_ANSI__).
+    * OpenWatcom wraps it in !defined(_NO_EXT_KEYS).
 
 This can be reviewed as compatibility issues arise. The preference is to use _wfopen_s() and _wfopen() as opposed to the wcsrtombs()
 fallback, so if you notice your compiler not detecting this properly I'm happy to look at adding support.
 */
 #if defined(_WIN32)
-    #if defined(_MSC_VER) || defined(__MINGW64__) || !defined(__STRICT_ANSI__)
+    #if defined(_MSC_VER) || defined(__MINGW64__) || (!defined(__STRICT_ANSI__) && !defined(_NO_EXT_KEYS))
         #define DRWAV_HAS_WFOPEN
     #endif
 #endif
@@ -6050,6 +6053,9 @@ two different ways to initialize a drwav object.
 /*
 REVISION HISTORY
 ================
+v0.12.15 - 2020-11-21
+  - Fix compilation with OpenWatcom.
+
 v0.12.14 - 2020-11-13
   - Minor code clean up.