add TextIsEqualCase and use in IsFileExtension

src/core.c

@@ -1845,7 +1845,7 @@ bool IsFileExtension(const char *fileName, const char *ext)
 
         for (int i = 0; i < extCount; i++)
         {
-            if (strcmp(fileExt, checkExts[i] + 1) == 0)
+            if (TextIsEqualCase(fileExt, checkExts[i] + 1))
             {
                 result = true;
                 break;

src/raylib.h

@@ -1196,6 +1196,7 @@ RLAPI int GetGlyphIndex(Font font, int codepoint);
 // Text strings management functions (no utf8 strings, only byte chars)
 // NOTE: Some strings allocate memory internally for returned strings, just be careful!
 RLAPI bool TextIsEqual(const char *text1, const char *text2);                               // Check if two text string are equal
+RLAPI bool TextIsEqualCase(const char *text1, const char *text2);                           // Check if two text strings are equal ignoring case
 RLAPI unsigned int TextLength(const char *text);                                            // Get text length, checks for '\0' ending
 RLAPI const char *TextFormat(const char *text, ...);                                        // Text formatting with variables (sprintf style)
 RLAPI const char *TextSubtext(const char *text, int position, int length);                  // Get a piece of a text string

src/text.c

@@ -1108,6 +1108,23 @@ bool TextIsEqual(const char *text1, const char *text2)
 
     return result;
 }
+// Check if two text string are equal ignoring case
+// REQUIRES: tolower()
+bool TextIsEqualCase(const char *text1, const char *text2)
+{
+    bool result = false;
+
+	while (tolower((unsigned char)(*text1)) == tolower((unsigned char)(*text2++)))
+	{
+		if(*text1++ == '\0')
+		{
+			result = true;
+			break;
+		}
+	}
+
+    return result;
+}
 
 // Get text length in bytes, check for \0 character
 unsigned int TextLength(const char *text)