Add support to Nix when building with Clang to use the Address Sanitizer (ASan)

nix_clang_asan_support.diff

diff --git a/Makefile b/Makefile
index 5040d2884..ac29e2526 100644
--- a/Makefile
+++ b/Makefile
@@ -27,11 +27,14 @@ makefiles = \
 OPTIMIZE = 1
 
 ifeq ($(OPTIMIZE), 1)
-  GLOBAL_CXXFLAGS += -O3
+  GLOBAL_CXXFLAGS += -O1
 else
   GLOBAL_CXXFLAGS += -O0 -U_FORTIFY_SOURCE
 endif
 
 include mk/lib.mk
 
-GLOBAL_CXXFLAGS += -g -Wall -include config.h -std=c++17 -I src
+# enable ASan - https://clang.llvm.org/docs/AddressSanitizer.html
+GLOBAL_CXXFLAGS += -fsanitize=address -fno-omit-frame-pointer -fno-optimize-sibling-calls -g -Wall -include config.h -std=c++17 -I src
+
+GLOBAL_LDFLAGS += -fsanitize=address
\ No newline at end of file
diff --git a/Makefile.config.in b/Makefile.config.in
index c8c4446b4..d9b1a2cd3 100644
--- a/Makefile.config.in
+++ b/Makefile.config.in
@@ -12,7 +12,8 @@ ENABLE_S3 = @ENABLE_S3@
 GTEST_LIBS = @GTEST_LIBS@
 HAVE_LIBCPUID = @HAVE_LIBCPUID@
 HAVE_SECCOMP = @HAVE_SECCOMP@
-LDFLAGS = @LDFLAGS@
+LDFLAGS = @LDFLAGS@ -fsanitize=address
+LD = @CXX@
 LIBARCHIVE_LIBS = @LIBARCHIVE_LIBS@
 LIBBROTLI_LIBS = @LIBBROTLI_LIBS@
 LIBCURL_LIBS = @LIBCURL_LIBS@
diff --git a/mk/libraries.mk b/mk/libraries.mk
index ffd7b5610..bdd595d8a 100644
--- a/mk/libraries.mk
+++ b/mk/libraries.mk
@@ -79,7 +79,8 @@ define build-library
     else
       ifndef HOST_DARWIN
         ifndef HOST_CYGWIN
-          $(1)_LDFLAGS += -Wl,-z,defs
+          # This is known to cause problems for AddressSanitizer
+          # $(1)_LDFLAGS += -Wl,-z,defs
         endif
       endif
     endif