Don't include gdbarch.h from defs.h

I touched symtab.h and was surprised to see how many files were
rebuilt.  I looked into it a bit, and found that defs.h includes
gdbarch.h, which in turn includes many things.

gdbarch.h is only needed by a minority ofthe files in gdb, so this
patch removes the include from defs.h and updates the fallout.

I did "wc -l" on the files in build/gdb/.deps; this patch reduces the
line count from 139935 to 137030; so there are definitely future
build-time savings here.

Note that while I configured with --enable-targets=all, it's possible
that some *-nat.c file needs an update.  I could not test all of
these.  The buildbot caught a few problems along these lines.

gdb/ChangeLog
2019-07-10  Tom Tromey  <tom@tromey.com>

	* defs.h: Don't include gdbarch.h.
	* aarch64-ravenscar-thread.c, aarch64-tdep.c, alpha-bsd-tdep.h,
	alpha-linux-tdep.c, alpha-mdebug-tdep.c, arch-utils.h, arm-tdep.h,
	ax-general.c, btrace.c, buildsym-legacy.c, buildsym.h, c-lang.c,
	cli/cli-decode.h, cli/cli-dump.c, cli/cli-script.h,
	cli/cli-style.h, coff-pe-read.h, compile/compile-c-support.c,
	compile/compile-cplus.h, compile/compile-loc2c.c, corefile.c,
	cp-valprint.c, cris-linux-tdep.c, ctf.c, d-lang.c, d-namespace.c,
	dcache.c, dicos-tdep.c, dictionary.c, disasm-selftests.c,
	dummy-frame.c, dummy-frame.h, dwarf2-frame-tailcall.c,
	dwarf2expr.c, expression.h, f-lang.c, frame-base.c,
	frame-unwind.c, frv-linux-tdep.c, gdbarch-selftests.c, gdbtypes.h,
	go-lang.c, hppa-nbsd-tdep.c, hppa-obsd-tdep.c, i386-dicos-tdep.c,
	i386-tdep.h, ia64-vms-tdep.c, interps.h, language.c,
	linux-record.c, location.h, m2-lang.c, m32r-linux-tdep.c,
	mem-break.c, memattr.c, mn10300-linux-tdep.c, nios2-linux-tdep.c,
	objfiles.h, opencl-lang.c, or1k-linux-tdep.c, p-lang.c,
	parser-defs.h, ppc-tdep.h, probe.h, python/py-record-btrace.c,
	record-btrace.c, record.h, regcache-dump.c, regcache.h,
	riscv-fbsd-tdep.c, riscv-linux-tdep.c, rust-exp.y,
	sh-linux-tdep.c, sh-nbsd-tdep.c, source-cache.c,
	sparc-nbsd-tdep.c, sparc-obsd-tdep.c, sparc-ravenscar-thread.c,
	sparc64-fbsd-tdep.c, std-regs.c, target-descriptions.h,
	target-float.c, tic6x-linux-tdep.c, tilegx-linux-tdep.c, top.c,
	tracefile.c, trad-frame.c, type-stack.h, ui-style.c, utils.c,
	utils.h, valarith.c, valprint.c, varobj.c, x86-tdep.c,
	xml-support.h, xtensa-linux-tdep.c, cli/cli-cmds.h: Update.
	* s390-linux-nat.c, procfs.c, inf-ptrace.c: Likewise.

1 files changed, 2 insertions, 0 deletions

diff --git a/gdb/expression.h b/gdb/expression.h
index 841bf98..02b51f5 100644
--- a/gdb/expression.h
+++ b/gdb/expression.h
@@ -20,6 +20,8 @@
 #if !defined (EXPRESSION_H)
 #define EXPRESSION_H 1
 
+#include "gdbtypes.h"
+
 /* While parsing expressions we need to track the innermost lexical block
    that we encounter.  In some situations we need to track the innermost
    block just for symbols, and in other situations we want to track the