Fix gphoto2 library detection

Use pkg-config file, if possible

Signed-off-by: Slávek Banko <slavek.banko@axis.cz>
(cherry picked from commit 6134b7ce07)

digikam/configure.in.in

@@ -124,18 +124,35 @@ AC_SUBST(LCMS_LIBS)
 #
 #------------------------------------------------------------------
 
-AC_PATH_PROG(GPHOTO_CONFIG,gphoto2-config)
-AC_PATH_PROG(GPHOTO_PORT_CONFIG,gphoto2-port-config)
-if test -n "${GPHOTO_CONFIG}"; then
-  GPHOTO_VERSION="`$GPHOTO_CONFIG --version`"
-  case "${GPHOTO_VERSION}" in "libgphoto2 2.5"*) CXXFLAGS="$CXXFLAGS -DHAVE_GPHOTO25";; esac
-  GPHOTO_CFLAGS="`$GPHOTO_CONFIG --cflags`"
+KDE_PKG_CHECK_MODULES(GPHOTO2, libgphoto2 >= 2.5,
+         [have_libgphoto2=yes, have_gphoto25=yes], have_libgphoto2=no)
+if test "x$have_libgphoto2" = "xno"; then
+  KDE_PKG_CHECK_MODULES(GPHOTO2, libgphoto2,
+         have_libgphoto2=yes, have_libgphoto2=no)
+fi
+if test "x$have_libgphoto2" = "xno"; then
+  AC_PATH_PROG(GPHOTO_CONFIG,gphoto2-config)
+  AC_PATH_PROG(GPHOTO_PORT_CONFIG,gphoto2-port-config)
+  if test -n "${GPHOTO_CONFIG}"; then
+    GPHOTO_VERSION="`$GPHOTO_CONFIG --version`"
+    case "${GPHOTO_VERSION}" in "libgphoto2 2.5"*) CXXFLAGS="$CXXFLAGS -DHAVE_GPHOTO25";; esac
+    GPHOTO_CFLAGS="`$GPHOTO_CONFIG --cflags`"
+    AC_SUBST(GPHOTO_CFLAGS)
+    LIB_GPHOTO="`$GPHOTO_CONFIG --libs` `$GPHOTO_PORT_CONFIG --libs`"
+    AC_SUBST(LIB_GPHOTO)
+  else
+    AC_MSG_WARN([gPhoto2 not found.])
+    DO_NOT_COMPILE="digikam $DO_NOT_COMPILE"
+  fi
+else
+  if test "x$have_gphoto25" = "xyes"; then
+    GPHOTO_CFLAGS="$GPHOTO2_CFLAGS -DHAVE_GPHOTO25"
+  else
+    GPHOTO_CFLAGS="$GPHOTO2_CFLAGS"
+  fi
+  LIB_GPHOTO="$GPHOTO2_LIBS"
   AC_SUBST(GPHOTO_CFLAGS)
-  LIB_GPHOTO="`$GPHOTO_CONFIG --libs` `$GPHOTO_PORT_CONFIG --libs`"
   AC_SUBST(LIB_GPHOTO)
-else
-  AC_MSG_WARN([gPhoto2 not found.])
-  DO_NOT_COMPILE="digikam $DO_NOT_COMPILE"
 fi
 
 CXXFLAGS="$CXXFLAGS -DQT_CLEAN_NAMESPACE"