Have libmdb.pc reflect --disable-glib

Also try to work around Travis issues with sudo, libtool, and clang

.travis.yml

@@ -200,6 +200,5 @@ script:
   - ./src/util/mdb-sql -i test/sql/nwind.sql test/data/nwind.mdb
   - ./src/util/mdb-queries test/data/ASampleDatabase.accdb qryCostsSummedByOwner
   - env MDBPATH=test/data ./src/odbc/unittest
-  - sudo make install
-  - pkg-config libmdb --exists
-  - pkg-config libmdbsql --exists
+  - env PKG_CONFIG_PATH=. pkg-config libmdb --exists
+  - env PKG_CONFIG_PATH=. pkg-config libmdbsql --exists

configure.ac

@@ -212,9 +212,11 @@ AC_ARG_ENABLE(glib,
         [enable_glib=$enableval], [enable_glib=yes])
 
 if test "$enable_glib" = "yes"; then
-    PKG_CHECK_MODULES([GLIB], [glib-2.0], HAVE_GLIB=true, HAVE_GLIB=false)
+    GLIB_PACKAGE=glib-2.0
+    PKG_CHECK_MODULES([GLIB], [GLIB_PACKAGE], HAVE_GLIB=true, HAVE_GLIB=false)
     if test "x$HAVE_GLIB" = "xtrue"; then
         GLIB_CFLAGS="$GLIB_CFLAGS -DHAVE_GLIB=1"
+        AC_SUBST(GLIB_PACKAGE)
     else
         enable_glib=no
     fi

libmdb.pc.in

@@ -9,7 +9,7 @@ includedir=@includedir@
 
 Name: libmdb
 Description: core MDB file support library
-Requires: glib-2.0
+Requires: @GLIB_PACKAGE@
 Version: @VERSION@
 Libs: -L${libdir} -lmdb
 Cflags: