Add -fpermissive to linux standard c++ option define in linux.cf

Remove from individual Imakefiles.

Also, remove '#if 0' block in linux.cf, and remove empty
LinuxMachineDefines. This should be working correctly.  If not, let me
know.

cde/programs/dtprintinfo/Imakefile

@@ -23,10 +23,6 @@ all:: $(DTPRINTINFO_GEN)
 .NO_PARALLEL:
 #endif
 
-#if defined(LinuxArchitecture)
-CXXEXTRA_DEFINES = -fpermissive
-#endif
-
 INCLUDES = -I. -I./UI -I./libUI -I./util -I./libUI/MotifUI \
 	-I./objects -I./objects/PrintObj