(BOOT_CFLAGS, STMP_FIXPROTO, STMP_FIXPROTO): New, moved from x-linux.

From-SVN: r11932

gcc/config/t-linux

+# The following is needed when compiling stages 2 and 3 because gcc's
+# limits.h must be picked up before /usr/include/limits.h.  This is
+# because each does an #include_next of the other if the other hasn't
+# been included. /usr/include/limits.h loses if it gets found first
+# because /usr/include is at the end of the search order.  When a
+# new version of gcc is released, gcc's limits.h hasn't been installed
+# yet and hence isn't found.
+BOOT_CFLAGS = -O $(CFLAGS) -Iinclude
+
+# Don't run fixproto
+STMP_FIXPROTO =
+
+# Don't install "assert.h" in gcc. We use the one in glibc.
+INSTALL_ASSERT_H =
+
 # Linux uses crtbeginS.o and crtendS.o. Don't compile 
 # crtbegin.o and crtend.o with -fPIC.
 CRTSTUFF_T_CFLAGS=-fomit-frame-pointer -finhibit-size-directive \