Fix GH-8160: ZTS support on Alpine is broken

We need to export `__MUSL__` so that phpize builds can see the proper
macro, and also need to fix "_tsrm_ls_cache" usage for musl.

Closes GH-8180.

Author: mvorisek

NEWS

@@ -6,6 +6,7 @@ PHP                                                                        NEWS
   . Fixed freeing of internal attribute arguments. (Bob)
   . Fixed bug GH-8070 (memory leak of internal function attribute hash).
     (Tim Düsterhus)
+  . Fixed bug GH-8160 (ZTS support on Alpine is broken). (Michael Voříšek)
 
 - Intl:
   . Fixed bug GH-8142 (Compilation error on cygwin). (David Carlier)

TSRM/TSRM.c

@@ -736,13 +736,13 @@ TSRM_API size_t tsrm_get_ls_cache_tcb_offset(void)
 #if defined(__APPLE__) && defined(__x86_64__)
     // TODO: Implement support for fast JIT ZTS code ???
 	return 0;
-#elif defined(__x86_64__) && defined(__GNUC__) && !defined(__FreeBSD__) && !defined(__OpenBSD__)
+#elif defined(__x86_64__) && defined(__GNUC__) && !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__MUSL__)
 	size_t ret;
 
 	asm ("movq _tsrm_ls_cache@gottpoff(%%rip),%0"
           : "=r" (ret));
 	return ret;
-#elif defined(__i386__) && defined(__GNUC__) && !defined(__FreeBSD__) && !defined(__OpenBSD__)
+#elif defined(__i386__) && defined(__GNUC__) && !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__MUSL__)
 	size_t ret;
 
 	asm ("leal _tsrm_ls_cache@ntpoff,%0"

configure.ac

@@ -260,7 +260,7 @@ AC_MSG_CHECKING([whether we are using musl libc])
 if command -v ldd >/dev/null && ldd --version 2>&1 | grep -q ^musl
 then
   AC_MSG_RESULT(yes)
-  CPPFLAGS="$CPPFLAGS -D__MUSL__"
+  AC_DEFINE([__MUSL__], [1], [Define when using musl libc])
 else
   AC_MSG_RESULT(no)
 fi

ext/opcache/jit/zend_jit_x86.dasc

@@ -2974,7 +2974,7 @@ static int zend_jit_setup(void)
 # elif defined(__GNUC__) && defined(__x86_64__)
 	tsrm_ls_cache_tcb_offset = tsrm_get_ls_cache_tcb_offset();
 	if (tsrm_ls_cache_tcb_offset == 0) {
-#if defined(__has_attribute) && __has_attribute(tls_model) && !defined(__FreeBSD__) && !defined(__OpenBSD__)
+#if defined(__has_attribute) && __has_attribute(tls_model) && !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__MUSL__)
 		size_t ret;
 
 		asm ("movq _tsrm_ls_cache@gottpoff(%%rip),%0"
@@ -2993,7 +2993,7 @@ static int zend_jit_setup(void)
 # elif defined(__GNUC__) && defined(__i386__)
 	tsrm_ls_cache_tcb_offset = tsrm_get_ls_cache_tcb_offset();
 	if (tsrm_ls_cache_tcb_offset == 0) {
-#if !defined(__FreeBSD__) && !defined(__OpenBSD__)
+#if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__MUSL__)
 		size_t ret;
 
 		asm ("leal _tsrm_ls_cache@ntpoff,%0\n"