bugfix: compiler wrappers should handle extra spaces between arguments (#22725)

In the face of two consecutive spaces in the command line, the compiler wrapper would skip all remaining arguments, causing problems building py-scipy with Intel compiler. This PR solves the problem.

* Fixed compiler wrapper in the face of extra spaces between arguments

Co-authored-by: Elizabeth Fischer <elizabeth.fischer@alaska.edu>

lib/spack/env/cc

@@ -277,10 +277,18 @@ other_args=()
 isystem_system_includes=()
 isystem_includes=()
 
-while [ -n "$1" ]; do
+while [ $# -ne 0 ]; do
+
     # an RPATH to be added after the case statement.
     rp=""
 
+    # Multiple consecutive spaces in the command line can
+    # result in blank arguments
+    if [ -z "$1" ]; then
+        shift
+        continue
+    fi
+
     case "$1" in
         -isystem*)
             arg="${1#-isystem}"