Unify ASan options in make builds

Use a common set of options when building with Asan without CMake.
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 870797f..ca08f9c 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -137,6 +137,9 @@
         export MAKEFLAGS="-j"
     fi
 
+    # CFLAGS and LDFLAGS for Asan builds that don't use CMake
+    ASAN_CFLAGS='-Werror -Wall -Wextra -fsanitize=address'
+
     # Gather the list of available components. These are the functions
     # defined in this script whose name starts with "component_".
     # Parse the script with sed, because in sh there is no way to list
@@ -920,7 +923,7 @@
     # Build once with -O0, to compile out the i386 specific inline assembly
     msg "build: i386, make, gcc -O0 (ASan build)" # ~ 30s
     scripts/config.pl full
-    make CC=gcc CFLAGS='-O0 -Werror -Wall -Wextra -m32 -fsanitize=address' LDFLAGS='-m32 -fsanitize=address'
+    make CC=gcc CFLAGS="$ASAN_CFLAGS -m32 -O0" LDFLAGS="-m32 $ASAN_CFLAGS"
 
     msg "test: i386, make, gcc -O0 (ASan build)"
     make test
@@ -936,7 +939,7 @@
     # Build again with -O1, to compile in the i386 specific inline assembly
     msg "build: i386, make, gcc -O1 (ASan build)" # ~ 30s
     scripts/config.pl full
-    make CC=gcc CFLAGS='-O1 -Werror -Wall -Wextra -m32 -fsanitize=address' LDFLAGS='-m32 -fsanitize=address'
+    make CC=gcc CFLAGS="$ASAN_CFLAGS -m32 -O1" LDFLAGS="-m32 $ASAN_CFLAGS"
 
     msg "test: i386, make, gcc -O1 (ASan build)"
     make test