Answer by Huckle for OS detecting makefile

I ran into this problem today and I needed it on Solaris so here is a POSIX standard way to do (something very close to) this.

#Detect OSUNAME = `uname`# Build based on OS nameDetectOS:    -@make $(UNAME)# OS is Linux, use GCCLinux: program.c    @SHELL_VARIABLE="-D_LINUX_STUFF_HERE_"    rm -f program    gcc $(SHELL_VARIABLE) -o program program.c# OS is Solaris, use c99SunOS: program.c    @SHELL_VARIABLE="-D_SOLARIS_STUFF_HERE_"    rm -f program    c99 $(SHELL_VARIABLE) -o program program.c