Require GCC in test build; adjust test messages

tests/library-smoke.sh

@@ -1,8 +1,11 @@
 #!/usr/bin/bash
 
 gcc -x c -o smoke_test -lreport -Wno-implicit-function-declaration - <<EOF
+#include <stdio.h>
 int main(void) {
     libreport_init();
+    printf("libreport initialized OK\n");
+    return 0;
 }
 EOF
 ./smoke_test

tests/smoke.fmf

@@ -1,12 +1,14 @@
 summary: Basic smoke test for libreport
-require: gcc
 prepare:
     how: install
     # Do not attempt to install conflicting subpackages.
     exclude:
         - abrt-atomic
         - python3-abrt-container-addon
+    # Prerequisite for smoke testing liblibreport.
+    package:
+        - gcc
 execute:
     script: |
-        tests/smoke.sh
+        tests/library-smoke.sh
         report-cli --version