Patch to make gRPC v1.4.2 build using GCC v7+

grpc-build-against-gcc7.patch

--- templates/Makefile.template	2017-07-11 18:11:30.000000000 -0300
+++ templates/Makefile.template	2017-08-01 19:28:51.077076488 -0300
@@ -225,7 +225,7 @@
   HOST_LD ?= $(LD)
   HOST_LDXX ?= $(LDXX)
 
-  CFLAGS += -std=c99 -Wsign-conversion -Wconversion ${' '.join(warning_var('$(W_%s)', warning) for warning in PREFERRED_WARNINGS)}
+  CFLAGS += -std=c99 -Wsign-conversion -Wno-conversion -Wno-implicit-fallthrough ${' '.join(warning_var('$(W_%s)', warning) for warning in PREFERRED_WARNINGS)}
   CXXFLAGS += -std=c++11
   % for arg in ['CFLAGS', 'CXXFLAGS', 'CPPFLAGS', 'LDFLAGS', 'DEFINES']:
   %  if defaults.get('global', []).get(arg, None) is not None:

Please note that this patch is for v1.4.2 release, this is already fixed in master.

gRPC still using openssl-1.0 API, and some(most of?) systems is using openssl-1.1 by default.
you'll need re-generate the Makefile with correct openssl version.

On ArchLinux you can do this as follow:

export PKG_CONFIG_PATH=/usr/lib/openssl-1.0/pkgconfig
# and then re-generate Makefile
./tools/buildgen/generate_projects.sh