Add test case for empty fields

Make sure we don't run into the bug fixed by 6a27c57 again.

check/check-cflags

@@ -11,5 +11,9 @@ set -e
 
 ARGS="--cflags simple"
 RESULT=""
-
 run_test
+
+ARGS="--cflags fields-blank"
+RESULT=""
+run_test
+

check/check-libs

@@ -15,5 +15,8 @@ if [ "$list_indirect_deps" = "yes" ]; then
 else
     RESULT="-lsimple"
 fi
-
+run_test
+
+ARGS="--libs fields-blank"
+RESULT=""
 run_test

check/fields-blank.pc

@@ -0,0 +1,11 @@
+prefix=/usr
+exec_prefix=${prefix}
+libdir=${exec_prefix}/lib
+includedir=${prefix}/include
+
+Name: Simple test
+Description: Dummy pkgconfig test package for testing pkgconfig
+Version: 1.0.0
+Requires:
+Libs: 
+Cflags: