MFH: fix #40578 (imagettftext() multithreading issue)

NEWS

@@ -9,6 +9,7 @@ PHP                                                                        NEWS
 - Added --ri switch to CLI which allows to check extension information. (Marcus)
 - Added tidyNode::getParent() method (John, Nuno)
 - Fixed zend_llist_remove_tail (Michael Wallner, Dmitry)
+- Fixed bug #40578 (imagettftext() multithreading issue). (Tony)
 - Fixed bug #40576 (double values are truncated to 6 decimal digits when 
   encoding). (Tony)
 - Fixed bug #40560 (DIR functions do not work on root UNC path). (Dmitry)

ext/gd/libgd/gdft.c

@@ -192,6 +192,16 @@ typedef struct
 #include "jisx0208.h"
 #endif
 
+extern int any2eucjp (char *, char *, unsigned int);
+
+/* Persistent font cache until explicitly cleared */
+/* Fonts can be used across multiple images */
+
+/* 2.0.16: thread safety (the font cache is shared) */
+gdMutexDeclare(gdFontCacheMutex);
+static gdCache_head_t *fontCache = NULL;
+static FT_Library library;
+
 #define Tcl_UniChar int
 #define TCL_UTF_MAX 3
 static int gdTcl_UtfToUniChar (char *str, Tcl_UniChar * chPtr)
@@ -688,8 +698,10 @@ static char * gdft_draw_bitmap (gdCache_head_t *tc_cache, gdImage * im, int fg,
 				} else {
 					/* find antialised color */
 					tc_key.bgcolor = *pixel;
+					gdMutexLock(gdFontCacheMutex);
 					tc_elem = (tweencolor_t *) gdCacheGet(tc_cache, &tc_key);
 					*pixel = tc_elem->tweencolor;
+					gdMutexUnlock(gdFontCacheMutex);
 				}
 			}
 		}
@@ -703,16 +715,6 @@ gdroundupdown (FT_F26Dot6 v1, int updown)
 	return (!updown) ? (v1 < 0 ? ((v1 - 63) >> 6) : v1 >> 6) : (v1 > 0 ? ((v1 + 63) >> 6) : v1 >> 6);
 }
 
-extern int any2eucjp (char *, char *, unsigned int);
-
-/* Persistent font cache until explicitly cleared */
-/* Fonts can be used across multiple images */
-
-/* 2.0.16: thread safety (the font cache is shared) */
-gdMutexDeclare(gdFontCacheMutex);
-static gdCache_head_t *fontCache = NULL;
-static FT_Library library;
-
 void gdFontCacheShutdown()
 {
 	if (fontCache) {