sys-devel/gdb: enable verbose gdb build, bug #695936

While tracing missing tinfo detection Victor noticed
lack of precise arguments to gdb's linker and compiler
commands.

Two issues fixed here:
- restore default V=1 build in custome Makefile snippet
- set --disable-dependency-tracking to top-level ./configure
  to reach ./configure files that actually define it.
  Top-level does not and thus tricks portage's econf()
  into not passing it on.

Reported-by: Victor Mataré
Bug: https://bugs.gentoo.org/695936
Package-Manager: Portage-2.3.76, Repoman-2.3.17
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/sys-devel/gdb/files/gdb-8.3.1-verbose-build.patch b/sys-devel/gdb/files/gdb-8.3.1-verbose-build.patch
new file mode 100644
index 000000000000..06aa6084d2d2
--- /dev/null
+++ b/sys-devel/gdb/files/gdb-8.3.1-verbose-build.patch
@@ -0,0 +1,13 @@
+Enable verbose build. By default gdb ignores even --disable-silent-rules.
+Override verbosity back to non-silent.
+
+https://bugs.gentoo.org/695936
+--- a/gdb/silent-rules.mk
++++ b/gdb/silent-rules.mk
+@@ -1,5 +1,4 @@
+-# If V is undefined or V=0 is specified, use the silent/verbose/compact mode.
+-V ?= 0
++V ?= 1
+ ifeq ($(V),0)
+ ECHO_CXX =    @echo "  CXX    $@";
+ ECHO_CXXLD =  @echo "  CXXLD  $@";