Support scl-style quoted invocations

Resolves: RHEL-94760

gcc-toolset-15.spec

@@ -266,6 +266,7 @@ fi
 %changelog
 * Tue Jun 10 2025 Siddhesh Poyarekar <siddhesh@redhat.com> - 15.0-7
 - Man page and documentation updates (RHEL-95996)
+- Support scl-style quoted invocation (RHEL-94760)
 
 * Thu Jun  5 2025 Siddhesh Poyarekar <siddhesh@redhat.com> - 15.0-6
 - Split out scripts into a -runtime package on RHEL10 (RHEL-94841)

gcc-toolset-env.in

@@ -5,6 +5,10 @@
 
 if [ -z "$1" ]; then
   exec /usr/bin/sh
+# Compatibility with `scl enable`, where the entire command shows up as a
+# single argument.
+if [ -z "$2" ]; then
+  exec sh -c "$@"
 else
   exec "$@"
 fi