Fix build with -std=

When building in strict mode (e.g. -std=c11), compilation of
main/debug_gdb_scripts.c fails because asm() is not a standard top level
statement. __asm__() however can be reserved by the compiler even in strict
mode.

Partially fixes GH-21215. IR needs a similar fix (dstogov/ir#128).
Closes GH-21226.

NEWS

@@ -10,6 +10,7 @@ PHP                                                                        NEWS
     accessing properties on Reflection LazyProxy via isset()). (Arnaud)
   . Fixed OSS-Fuzz #478009707 (Borked assign-op/inc/dec on untyped hooked
     property backing value). (ilutov)
+  . Fixed bug GH-21215 (Build fails with -std=). (Arnaud)
 
 - Curl:
   . Fixed bug GH-21023 (CURLOPT_XFERINFOFUNCTION crash with a null callback).

main/debug_gdb_scripts.c

@@ -6,7 +6,7 @@
  *
  * See https://sourceware.org/gdb/current/onlinedocs/gdb.html/dotdebug_005fgdb_005fscripts-section.html#dotdebug_005fgdb_005fscripts-section
  */
-asm(
+__asm__(
     ".pushsection \".debug_gdb_scripts\", \"MS\",%progbits,1\n"
     ".byte 4 /* Python Text */\n"
     ".ascii \"gdb.inlined-script\\n\"\n"

scripts/gdb/debug_gdb_scripts_gen.php

@@ -27,7 +27,7 @@ $ccode = sprintf(
      *
      * See https://sourceware.org/gdb/current/onlinedocs/gdb.html/dotdebug_005fgdb_005fscripts-section.html#dotdebug_005fgdb_005fscripts-section
      */
-    asm(
+    __asm__(
         ".pushsection \".debug_gdb_scripts\", \"MS\",%%progbits,1\n"
         ".byte 4 /* Python Text */\n"
         ".ascii \"gdb.inlined-script\\n\"\n"