Removed SDL_bool in favor of plain bool

We require stdbool.h in the build environment, so we might as well use the plain bool type.

If your environment doesn't have stdbool.h, this simple replacement will suffice:
typedef signed char bool;

src/cpuinfo/SDL_cpuinfo.c

@@ -1035,72 +1035,72 @@ void SDL_QuitCPUInfo(void) {
 
 #define CPU_FEATURE_AVAILABLE(f) ((SDL_GetCPUFeatures() & (f)) ? true : false)
 
-SDL_bool SDL_HasAltiVec(void)
+bool SDL_HasAltiVec(void)
 {
     return CPU_FEATURE_AVAILABLE(CPU_HAS_ALTIVEC);
 }
 
-SDL_bool SDL_HasMMX(void)
+bool SDL_HasMMX(void)
 {
     return CPU_FEATURE_AVAILABLE(CPU_HAS_MMX);
 }
 
-SDL_bool SDL_HasSSE(void)
+bool SDL_HasSSE(void)
 {
     return CPU_FEATURE_AVAILABLE(CPU_HAS_SSE);
 }
 
-SDL_bool SDL_HasSSE2(void)
+bool SDL_HasSSE2(void)
 {
     return CPU_FEATURE_AVAILABLE(CPU_HAS_SSE2);
 }
 
-SDL_bool SDL_HasSSE3(void)
+bool SDL_HasSSE3(void)
 {
     return CPU_FEATURE_AVAILABLE(CPU_HAS_SSE3);
 }
 
-SDL_bool SDL_HasSSE41(void)
+bool SDL_HasSSE41(void)
 {
     return CPU_FEATURE_AVAILABLE(CPU_HAS_SSE41);
 }
 
-SDL_bool SDL_HasSSE42(void)
+bool SDL_HasSSE42(void)
 {
     return CPU_FEATURE_AVAILABLE(CPU_HAS_SSE42);
 }
 
-SDL_bool SDL_HasAVX(void)
+bool SDL_HasAVX(void)
 {
     return CPU_FEATURE_AVAILABLE(CPU_HAS_AVX);
 }
 
-SDL_bool SDL_HasAVX2(void)
+bool SDL_HasAVX2(void)
 {
     return CPU_FEATURE_AVAILABLE(CPU_HAS_AVX2);
 }
 
-SDL_bool SDL_HasAVX512F(void)
+bool SDL_HasAVX512F(void)
 {
     return CPU_FEATURE_AVAILABLE(CPU_HAS_AVX512F);
 }
 
-SDL_bool SDL_HasARMSIMD(void)
+bool SDL_HasARMSIMD(void)
 {
     return CPU_FEATURE_AVAILABLE(CPU_HAS_ARM_SIMD);
 }
 
-SDL_bool SDL_HasNEON(void)
+bool SDL_HasNEON(void)
 {
     return CPU_FEATURE_AVAILABLE(CPU_HAS_NEON);
 }
 
-SDL_bool SDL_HasLSX(void)
+bool SDL_HasLSX(void)
 {
     return CPU_FEATURE_AVAILABLE(CPU_HAS_LSX);
 }
 
-SDL_bool SDL_HasLASX(void)
+bool SDL_HasLASX(void)
 {
     return CPU_FEATURE_AVAILABLE(CPU_HAS_LASX);
 }