configure: Use pkg-config --exists rather than --modversion

With --modversion we were asking for output that we were just throwing
away anyway. The --exists option does just what we want, (no output
and communivating only via return value).

Also, --exists allows for testing versions of the package as well.

diff --git a/configure b/configure
index bab25016a1162ecadf3e965a083d37594ac179d5..fba075dd0e8a16371ba7c0e42cb2915b5dbeaeea 100755 (executable)
--- a/configure
+++ b/configure
@@ -220,7 +220,7 @@ fi
 printf "Checking for GMime development files... "
 have_gmime=0
 for gmimepc in gmime-2.6 gmime-2.4; do
-    if pkg-config --modversion $gmimepc > /dev/null 2>&1; then
+    if pkg-config --exists $gmimepc; then
        printf "Yes ($gmimepc).\n"
        have_gmime=1
        gmime_cflags=$(pkg-config --cflags $gmimepc)
@@ -233,7 +233,7 @@ if [ "$have_gmime" = "0" ]; then
 fi
 
 printf "Checking for talloc development files... "
-if pkg-config --modversion talloc > /dev/null 2>&1; then
+if pkg-config --exists talloc; then
     printf "Yes.\n"
     have_talloc=1
     talloc_cflags=$(pkg-config --cflags talloc)
@@ -246,7 +246,7 @@ else
 fi
 
 printf "Checking for valgrind development files... "
-if pkg-config --modversion valgrind > /dev/null 2>&1; then
+if pkg-config --exists valgrind; then
     printf "Yes.\n"
     have_valgrind=1
     valgrind_cflags=$(pkg-config --cflags valgrind)
@@ -256,7 +256,7 @@ else
 fi
 
 if [ -z "${EMACSLISPDIR}" ]; then
-    if pkg-config --modversion emacs > /dev/null 2>&1; then
+    if pkg-config --exists emacs; then
        EMACSLISPDIR=$(pkg-config emacs --variable sitepkglispdir)
     else
        EMACSLISPDIR='$(prefix)/share/emacs/site-lisp'