[libxslt] Fix pkg-config related regressions in configure script

[Nick Wellnhofer <nwellnhof src gnome org>]

commit 76df4c960c7247d82bf1c26344e76236cb37a175
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Thu Sep 14 16:24:16 2017 +0200

    Fix pkg-config related regressions in configure script
    
    Fix bashism in configure.in. Resulted in pkg-config never getting used
    for libxml if sh is not bash.
    
    Move pkg-config block to correct location. Rework libxml2 detection
    logic.
    
    Fixes bugs 787602 and 787617.

 configure.in |   54 ++++++++++++++++++++++--------------------------------
 1 files changed, 22 insertions(+), 32 deletions(-)
---
diff --git a/configure.in b/configure.in
index d6aa366..d39a916 100644
--- a/configure.in
+++ b/configure.in
@@ -502,31 +502,10 @@ AC_ARG_WITH(libxml-src,
 AC_SUBST(LIBXML_SRC)
 
 dnl
-dnl Try pkg-config first if nothing is set
-dnl
-
-if test "x$LIBXML_CONFIG_PREFIX" == "x" -a "x$LIBXML_SRC" == "x"
-then
-       PKG_CHECK_MODULES([LIBXML], [libxml-2.0 >= $LIBXML_REQUIRED_VERSION], [
-               LIBXML_MANUAL_SEARCH=no
-               WITH_MODULES="`$PKG_CONFIG --variable=modules libxml-2.0`"
-       ],
-       [
-               LIBXML_MANUAL_SEARCH=yes
-       ])
-else
-       LIBXML_MANUAL_SEARCH=yes
-fi
-
-if test "x$LIBXML_MANUAL_SEARCH" != "xno"
-then
-
-dnl
 dnl where is xml2-config
 dnl
 
 AC_SUBST(LIBXML_REQUIRED_VERSION)
-AC_MSG_CHECKING(for libxml libraries >= $LIBXML_REQUIRED_VERSION) 
 if test "x$LIBXML_CONFIG_PREFIX" != "x"
 then
        AC_PATH_TOOL([XML_CONFIG], [xml2-config], [false], [${LIBXML_CONFIG_PREFIX}/bin])
@@ -570,7 +549,8 @@ then
                LIBXML_SRC=`pwd`
                XML_CONFIG="${LIBXML_SRC}/xml2-config"
                LIBXML_CFLAGS="-I${LIBXML_SRC}/include"
-               LIBXML_LIBS="-L${LIBXML_SRC}"
+               LIBXML_LIBS="-L${LIBXML_SRC} `$XML_CONFIG --libs`"
+                WITH_MODULES="`$XML_CONFIG --modules`"
                cd $CWD
        else
                AC_MSG_ERROR([libxml source dir not found (${LIBXML_SRC}), typo?])
@@ -578,12 +558,24 @@ then
 fi
 
 dnl
+dnl Try pkg-config first if nothing is set
+dnl
+
+if test "x$LIBXML_CONFIG_PREFIX" = "x" -a "x$LIBXML_LIBS" = "x"
+then
+       PKG_CHECK_MODULES([LIBXML], [libxml-2.0 >= $LIBXML_REQUIRED_VERSION], [
+               WITH_MODULES="`$PKG_CONFIG --variable=modules libxml-2.0`"
+       ], [ ])
+fi
+
+dnl
 dnl make sure xml2-config is executable,
 dnl test version and init our variables
 dnl
 
-if ${XML_CONFIG} --libs print > /dev/null 2>&1
+if test "x$LIBXML_LIBS" = "x" && ${XML_CONFIG} --libs print > /dev/null 2>&1
 then
+        AC_MSG_CHECKING(for libxml libraries >= $LIBXML_REQUIRED_VERSION)
        XMLVERS=`$XML_CONFIG --version`
        if test VERSION_TO_NUMBER(echo $XMLVERS) -ge VERSION_TO_NUMBER(echo $LIBXML_REQUIRED_VERSION)
        then
@@ -591,17 +583,15 @@ then
        else
                AC_MSG_ERROR(Version $XMLVERS found. You need at least libxml2 $LIBXML_REQUIRED_VERSION for 
this version of libxslt)
        fi
-       LIBXML_LIBS="$LIBXML_LIBS `$XML_CONFIG --libs`"
-       if test "x$LIBXML_SRC" = "x"; then
-               LIBXML_CFLAGS="$LIBXML_CFLAGS `$XML_CONFIG --cflags`"
-       fi
-else
-       AC_MSG_ERROR([Could not find libxml2 anywhere, check ftp://xmlsoft.org/.])
+       LIBXML_LIBS="`$XML_CONFIG --libs`"
+       LIBXML_CFLAGS="`$XML_CONFIG --cflags`"
+        WITH_MODULES="`$XML_CONFIG --modules`"
 fi
 
-WITH_MODULES="`$XML_CONFIG --modules`"
-
-fi  # LIBXML_MANUAL_SEARCH
+if test "x$LIBXML_LIBS" = "x"
+then
+       AC_MSG_ERROR([Could not find libxml2 anywhere, check ftp://xmlsoft.org/.])
+fi
 
 
 AC_SUBST(CFLAGS)