gcc: update to version 7.4.0, Add config options

for coping libc.a, libpthread.a and libstdc++ to target.
Add config option to eliminate need for -lstdc++ and -lgcc_pic
switches when linking statically

Signed-off-by: Noble Pepper <noblepepper@gmail.com>

devel/gcc/patches/940-no-clobber-stamp-bits.patch

@@ -1,6 +1,28 @@
+commit 548d9a008ff265e9eaa3c7e0e6e301c6bd5645e6
+Author: Felix Fietkau <nbd@openwrt.org>
+Date:   Fri Dec 12 17:01:57 2014 +0000
+
+    gcc: don't clobber stamp-bits with a symlink to itself
+    
+    Several versions of gcc have an issue in libstdc++v3 where the build may
+    clobber stamp-bits with a link to itself.  This doesn't manifest itself
+    on all systems.  On several Ubuntu systems, this doesn't appear to be a
+    problem, but it is an issue on Fedora 16 systems.
+    
+    To fix the issue, we'll simply filter out stamp-bits from the symlinks
+    to be generated.
+    
+    Note: gcc 4.4.7 is unaffected by this issue, so no fix is necessary
+    there.
+    
+    Signed-off-by: John Szakmeister <john@szakmeister.net>
+    
+    SVN-Revision: 43669
+
+
 --- a/libstdc++-v3/include/Makefile.in
 +++ b/libstdc++-v3/include/Makefile.in
-@@ -1421,7 +1421,7 @@ stamp-bits: ${bits_headers}
+@@ -1474,7 +1474,7 @@ stamp-bits: ${bits_headers}
  	@$(STAMP) stamp-bits
  
  stamp-bits-sup: stamp-bits ${bits_sup_headers}