rely on pkg-config

Author: remicollet

config.m4

@@ -10,12 +10,27 @@ if test "$PHP_XZ" != "no"; then
   LIBNAME=lzma # you may want to change this
   LIBSYMBOL=lzma_stream_encoder # you most likely want to change this
 
-  PHP_CHECK_LIBRARY($LIBNAME,$LIBSYMBOL,
-  [
-    PHP_ADD_LIBRARY($LIBNAME, 1, XZ_SHARED_LIBADD)
-  ],[
-    AC_MSG_ERROR([wrong xz lib version or lib not found])
-  ])
+  AC_PATH_PROG(PKG_CONFIG, pkg-config, no)
+
+  AC_MSG_CHECKING(for liblzma)
+  if test -x "$PKG_CONFIG" && $PKG_CONFIG --exists liblzma; then
+    LIBLZMA_INCLINE=`$PKG_CONFIG liblzma --cflags`
+    LIBLZMA_LIBLINE=`$PKG_CONFIG liblzma --libs`
+    LIBLZMA_VERSION=`$PKG_CONFIG liblzma --modversion`
+    AC_MSG_RESULT(from pkg-config: version $LIBLZMA_VERSION)
+    PHP_EVAL_LIBLINE($LIBLZMA_LIBLINE, XZ_SHARED_LIBADD)
+    PHP_EVAL_INCLINE($LIBLZMA_INCLINE)
+  else
+    AC_MSG_WARN([not found using pkg-config, fallback to system directory])
+
+    PHP_CHECK_LIBRARY($LIBNAME,$LIBSYMBOL,
+    [
+      PHP_ADD_LIBRARY($LIBNAME, 1, XZ_SHARED_LIBADD)
+    ],[
+      AC_MSG_ERROR([wrong xz lib version or lib not found])
+    ])
+  fi
+
   PHP_SUBST(XZ_SHARED_LIBADD)
 
   PHP_NEW_EXTENSION(xz, xz.c xz_fopen_wrapper.c utils.c, $ext_shared, -DZEND_ENABLE_STATIC_TSRMLS_CACHE=1)