[gucharmap] build: Explicitly link to libdl

[Christian Persch <chpe src gnome org>]

commit 4ad97abc893ded93296f7c157631369fbddcf90a
Author: Christian Persch <chpe src gnome org>
Date:   Tue Mar 13 12:32:15 2018 +0100

    build: Explicitly link to libdl
    
    https://bugzilla.gnome.org/show_bug.cgi?id=794281

 configure.ac          |    7 +++++++
 gucharmap/Makefile.am |    1 +
 2 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index edbeafc..a4aa04a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -120,6 +120,13 @@ PKG_CHECK_MODULES([GTK],[
   freetype2
 ])
 
+sv_LIBS="$LIBS"
+LIBS=
+AC_SEARCH_LIBS([dlsym],[dl])
+LIBDL="$LIBS"
+LIBS="$sv_LIBS"
+AC_SUBST([LIBDL])
+
 GLIB_GENMARSHAL="$($PKG_CONFIG --variable=glib_genmarshal glib-2.0)"
 AC_SUBST([GLIB_GENMARSHAL])
 GLIB_MKENUMS="$($PKG_CONFIG --variable=glib_mkenums glib-2.0)"
diff --git a/gucharmap/Makefile.am b/gucharmap/Makefile.am
index e14b9d0..86b8b01 100644
--- a/gucharmap/Makefile.am
+++ b/gucharmap/Makefile.am
@@ -156,6 +156,7 @@ gucharmap_LDFLAGS = \
 gucharmap_LDADD = \
        libgucharmap@GUCHARMAP_LIBRARY_SUFFIX_U@.la     \
        $(GTK_LIBS)     \
+       $(LIBDL) \
        $(INTL_LIBS)
 
 dist_noinst_DATA = gucharmap-menus.ui