include libpng with pkg-config check for include path (fixes #1519300)

diff --git a/configure.ac b/configure.ac
index ad213e3f2694fd675b4ede54301069bd89754a29..395803b43d509b988b38414b12f0c2f7cec08c02 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -507,9 +507,9 @@ dnl *** NOTE: when we move to gtk 2.6 or later, we can remove the
 dnl ********* the override for g_ascii_strtod below...
 dnl sigc++-2.0 >= 2.0.12: using "visit_each" not available in 2.0.10
 if test $cc_vers_major -gt 3; then
-    PKG_CHECK_MODULES(INKSCAPE, gdkmm-2.4  glibmm-2.4  gtkmm-2.4  gtk+-2.0 >= 2.4.0  libxml-2.0 >= 2.6.11  libxslt >= 1.0.15  sigc++-2.0 >= 2.0.12  $ink_spell_pkg  gthread-2.0 >= 2.0)
+    PKG_CHECK_MODULES(INKSCAPE, gdkmm-2.4  glibmm-2.4  gtkmm-2.4  gtk+-2.0 >= 2.4.0  libxml-2.0 >= 2.6.11  libxslt >= 1.0.15  sigc++-2.0 >= 2.0.12  $ink_spell_pkg  gthread-2.0 >= 2.0 libpng >= 1.2)
 else
-    PKG_CHECK_MODULES(INKSCAPE, gdkmm-2.4  glibmm-2.4  gtkmm-2.4  gtk+-2.0 >= 2.4.0  libxml-2.0 >= 2.6.11  libxslt >= 1.0.15  sigc++-2.0 >= 2.0.11  $ink_spell_pkg  gthread-2.0 >= 2.0)
+    PKG_CHECK_MODULES(INKSCAPE, gdkmm-2.4  glibmm-2.4  gtkmm-2.4  gtk+-2.0 >= 2.4.0  libxml-2.0 >= 2.6.11  libxslt >= 1.0.15  sigc++-2.0 >= 2.0.11  $ink_spell_pkg  gthread-2.0 >= 2.0 libpng >= 1.2)
 fi
 
 dnl Shouldn't we test for libpng and libz?