Add a testcase for librpm development

Should've been in 6ec0e40 but at that
time cmake in Fedora had a dependency on rpm making this hard or
at least ugly. With that dependency fixed, we can now run cmake in there.

tests/mktree.fedora

@@ -111,6 +111,7 @@ case $CMD in
             binutils \
             bubblewrap \
             bzip2 \
+            cmake \
             coreutils \
             cpio \
             curl \

tests/rpmgeneral.at

@@ -58,6 +58,40 @@ RPMTEST_CHECK([runroot rpm --showrc],[0],
 [ignore])
 RPMTEST_CLEANUP
 
+AT_SETUP([rpm development])
+AT_KEYWORDS([devel])
+
+cat << EOF > CMakeLists.txt
+cmake_minimum_required(VERSION 3.18)
+project(trpm VERSION 1.0 DESCRIPTION "test rpm API" LANGUAGES C)
+
+find_package(rpm REQUIRED)
+add_executable(trpm trpm.c)
+target_link_libraries(trpm PRIVATE rpm::librpm)
+EOF
+
+cat << EOF > trpm.c
+#include <stdio.h>
+#include <rpm/rpmlib.h>
+
+int main(int argc, char *argv[])
+{
+	int rc = rpmReadConfigFiles(NULL, NULL);
+	printf("%s: %d\n", RPMVERSION, rc);
+	rpmFreeRpmrc();
+	return rc;
+}
+EOF
+
+cmake . && make
+
+RPMTEST_CHECK([[
+./trpm
+]],
+[0],
+[AT_PACKAGE_VERSION: 0]
+)
+RPMTEST_CLEANUP
 
 # ------------------------------
 # Check rpm --querytags