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/dtmail/MotifApp/Imakefile

@@ -34,11 +34,6 @@ EXTRA_C++OPTIONS =     -xF +p +w $(SPRO_V3_OPTIONS)
 
 #endif /* SunArchitecture */
 
-#if defined(LinuxArchitecture)
-CXXEXTRA_DEFINES = -fpermissive
-#endif
-
-
 HEADERS = 
 
 SRCS = \

cde/programs/dtmail/dtmail/Imakefile

@@ -16,10 +16,6 @@ DEFINES = -DRELEASE_NOTES -DDTMAIL_TOOLTALK -DDTEDITOR DtMailDefines
 DEPLIBS = ../MotifApp/libMotifApp.a ../libDtMail/libDtMail.a DepDtClientLibs
 LOCAL_LIBRARIES = ../libDtMail/libDtMail.a ../MotifApp/libMotifApp.a DtClientLibs
 
-#if defined(LinuxArchitecture)
-CXXEXTRA_DEFINES = -fpermissive
-#endif
-
 /* Sun needs the widechar library */
 #ifdef SunArchitecture
 SYS_LIBRARIES =	$(DYNLIBSYSLIB) $(ICONVSYSLIB) $(REGEXSYSLIB) -lw -lm

cde/programs/dtmail/dtmailpr/Imakefile

@@ -40,10 +40,6 @@ MT_LIBS		=	-i $(C++_LIB)  -lm -lw -lc
 SYS_LIBRARIES	=	-lintl -lnsl $(MT_LIBS) -lC
 #endif /* SunArchitecture */
 
-#if defined(LinuxArchitecture)
-CXXEXTRA_DEFINES = -fpermissive
-#endif
- 
 SRCS = main.C message.C mailbox.C utils.C
 OBJS = main.o message.o mailbox.o utils.o
 

cde/programs/dtmail/libDtMail/Common/Imakefile

@@ -14,10 +14,6 @@ DEPEND_DEFINES = $(CXXDEPENDINCLUDES)
 
 INCLUDES = -I. -I../../include -I../../include/utils -I$(CDELIBSRC)
 
-#if defined(LinuxArchitecture)
-CXXEXTRA_DEFINES = -fpermissive
-#endif
-
 #if HasVFork
 VFORK_DEFINES = -DHAS_VFORK
 #else

cde/programs/dtmail/libDtMail/RFC/Imakefile

@@ -14,10 +14,6 @@ DEPEND_DEFINES = $(CXXDEPENDINCLUDES)
 
 INCLUDES = -I. -I../Common -I../../include -I../../include/utils -I$(CDELIBSRC)
 
-#if defined(LinuxArchitecture)
-CXXEXTRA_DEFINES = -fpermissive
-#endif
-
 #if HasVFork
 VFORK_DEFINES = -DHAS_VFORK
 #else