[devhelp] Build against either webkit2gtk-3.0 or webkit2gtk-4.0

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 2dfa11071b862b971e8d3915caa11f1d390dec2c
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Mon Aug 11 10:25:15 2014 -0500

    Build against either webkit2gtk-3.0 or webkit2gtk-4.0
    
    The API changes were minor and none affected devhelp.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=734324

 configure.ac |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 00c67c7..e3a7a02 100644
--- a/configure.ac
+++ b/configure.ac
@@ -47,17 +47,24 @@ GNOME_COMPILE_WARNINGS([maximum])
 AC_CHECK_LIBM
 AC_SUBST(LIBM)
 
+# Pick from supported API versions of WebKit2
+PKG_CHECK_EXISTS([webkit2gtk-4.0], [
+       WEBKIT_PKGCONFIG=webkit2gtk-4.0
+], [
+       WEBKIT_PKGCONFIG=webkit2gtk-3.0
+])
+
 PKG_CHECK_MODULES(DEVHELP, [
   gthread-2.0 >= 2.10.0
   gtk+-3.0 >= 3.13.4
-  webkit2gtk-3.0 >= 2.0.0
+  $WEBKIT_PKGCONFIG >= 2.0.0
   gio-2.0 >= 2.37.3
 ])
 
 PKG_CHECK_MODULES(LIBDEVHELP, [
   gtk+-3.0 >= 3.12.0
   gio-2.0 >= 2.37.3
-  webkit2gtk-3.0 >= 2.0.0
+  $WEBKIT_PKGCONFIG >= 2.0.0
 ])
 
 AC_ARG_WITH(zlib, [  --with-zlib=DIR         use zlib in DIR], zlibdir=$with_zlib)