Allow CC and other environment variables to contain space when building
Currently if the value of CC or the like contains a space (most notably, CC=ccache gcc) the build fails like so:
;;; Note:
;;; Invoking external command:
;;; ccache gcc -I. -I/home/iguananaut/src/ecl/ecl/build/ -DECL_API -I/home/iguananaut/src/ecl/ecl/build/c -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -g -O2 -fPIC -D_THREAD_SAFE -Dlinux -I/home/iguananaut/src/ecl/ecl/src/c -c lsp/export.c -o lsp/export.o exec: No such file or directory
Condition of type: SIMPLE-ERROR
Error code 6 when executing
(RUN-PROGRAM "ccache gcc" ("-I." "-I/home/iguananaut/src/ecl/ecl/build/" "-DECL_API" "-I/home/iguananaut/src/ecl/ecl/build/c" "-D_GNU_SOURCE" "-D_FILE_OFFSET_BITS=64" "-g" "-O2" "-fPIC" "-D_THREAD_SAFE" "-Dlinux" "-I/home/iguananaut/src/ecl/ecl/src/c" "-c" "lsp/export.c" "-o" "lsp/export.o"))
Available restarts:
1. (CONTINUE) Continues anyway.
2. (ABORT) ABORT
Top level in: #<process TOP-LEVEL>.This fixes the issue generally by patching safe-run-program rather than checking for this case every time *cc*, *ld*, etc. are used.