Match PSDK definitions for LPCWAVEFORMATEX.

diff --git a/include/mmsystem.h b/include/mmsystem.h
index ac8482b..1565896 100644
--- a/include/mmsystem.h
+++ b/include/mmsystem.h
@@ -485,6 +485,7 @@
     WORD	cbSize;
 } WAVEFORMATEX, *LPWAVEFORMATEX, *NPWAVEFORMATEX, *PWAVEFORMATEX;
 #endif
+typedef const WAVEFORMATEX *LPCWAVEFORMATEX;
 
 UINT 		WINAPI 	waveOutGetNumDevs(void);
 UINT           WINAPI  waveOutGetDevCapsA(UINT_PTR,LPWAVEOUTCAPSA,UINT);
@@ -495,7 +496,7 @@
 UINT 		WINAPI 	waveOutGetErrorTextA(UINT,LPSTR,UINT);
 UINT 		WINAPI 	waveOutGetErrorTextW(UINT,LPWSTR,UINT);
 #define 	    	waveOutGetErrorText WINELIB_NAME_AW(waveOutGetErrorText)
-UINT           WINAPI  waveOutOpen(HWAVEOUT*,UINT,const LPWAVEFORMATEX,DWORD_PTR,DWORD_PTR,DWORD);
+MMRESULT        WINAPI  waveOutOpen(HWAVEOUT*,UINT,LPCWAVEFORMATEX,DWORD_PTR,DWORD_PTR,DWORD);
 UINT 		WINAPI 	waveOutClose(HWAVEOUT);
 UINT 		WINAPI 	waveOutPrepareHeader(HWAVEOUT,WAVEHDR*,UINT);
 UINT 		WINAPI 	waveOutUnprepareHeader(HWAVEOUT,WAVEHDR*,UINT);
@@ -518,7 +519,7 @@
 UINT 		WINAPI 	waveInGetErrorTextA(UINT,LPSTR,UINT);
 UINT 		WINAPI 	waveInGetErrorTextW(UINT,LPWSTR,UINT);
 #define 		waveInGetErrorText WINELIB_NAME_AW(waveInGetErrorText)
-UINT           WINAPI  waveInOpen(HWAVEIN*,UINT,const LPWAVEFORMATEX,DWORD_PTR,DWORD_PTR,DWORD);
+MMRESULT        WINAPI  waveInOpen(HWAVEIN*,UINT,LPCWAVEFORMATEX,DWORD_PTR,DWORD_PTR,DWORD);
 UINT 		WINAPI  waveInClose(HWAVEIN);
 UINT 		WINAPI  waveInPrepareHeader(HWAVEIN,WAVEHDR*,UINT);
 UINT 		WINAPI  waveInUnprepareHeader(HWAVEIN,WAVEHDR*,UINT);
@@ -1485,7 +1486,7 @@
 UINT		WINAPI	mixerGetNumDevs(void);
 UINT           WINAPI  mixerOpen(LPHMIXER,UINT,DWORD_PTR,DWORD_PTR,DWORD);
 UINT		WINAPI	mixerClose(HMIXER);
-UINT           WINAPI  mixerMessage(HMIXER,UINT,DWORD_PTR,DWORD_PTR);
+DWORD           WINAPI  mixerMessage(HMIXER,UINT,DWORD_PTR,DWORD_PTR);
 UINT           WINAPI  mixerGetDevCapsA(UINT_PTR,LPMIXERCAPSA,UINT);
 UINT           WINAPI  mixerGetDevCapsW(UINT_PTR,LPMIXERCAPSW,UINT);
 #define 		mixerGetDevCaps WINELIB_NAME_AW(mixerGetDevCaps)