Partially revert b82271e5

Automake generates a different libtool invocation if ?= is used.
More investigation needed but for now this is enough to fix make
check under macos.

lib/libvcc/vmodtool.py

@@ -66,7 +66,7 @@ vmod_LTLIBRARIES = libvmod_XXX.la
 libvmod_XXX_la_CFLAGS ?= \\
 \t@SAN_CFLAGS@
 
-libvmod_XXX_la_LDFLAGS ?= \\
+libvmod_XXX_la_LDFLAGS = \\
 \t-export-symbols-regex 'Vmod_XXX_Data' \\
 \t$(AM_LDFLAGS) \\
 \t$(VMOD_LDFLAGS) \\

lib/libvmod_blob/automake_boilerplate.am

@@ -15,7 +15,7 @@ vmod_LTLIBRARIES = libvmod_blob.la
 libvmod_blob_la_CFLAGS ?= \
 	@SAN_CFLAGS@
 
-libvmod_blob_la_LDFLAGS ?= \
+libvmod_blob_la_LDFLAGS = \
 	-export-symbols-regex 'Vmod_blob_Data' \
 	$(AM_LDFLAGS) \
 	$(VMOD_LDFLAGS) \

lib/libvmod_cookie/automake_boilerplate.am

@@ -15,7 +15,7 @@ vmod_LTLIBRARIES = libvmod_cookie.la
 libvmod_cookie_la_CFLAGS ?= \
 	@SAN_CFLAGS@
 
-libvmod_cookie_la_LDFLAGS ?= \
+libvmod_cookie_la_LDFLAGS = \
 	-export-symbols-regex 'Vmod_cookie_Data' \
 	$(AM_LDFLAGS) \
 	$(VMOD_LDFLAGS) \

lib/libvmod_debug/automake_boilerplate.am

@@ -15,7 +15,7 @@ vmod_LTLIBRARIES = libvmod_debug.la
 libvmod_debug_la_CFLAGS ?= \
 	@SAN_CFLAGS@
 
-libvmod_debug_la_LDFLAGS ?= \
+libvmod_debug_la_LDFLAGS = \
 	-export-symbols-regex 'Vmod_debug_Data' \
 	$(AM_LDFLAGS) \
 	$(VMOD_LDFLAGS) \

lib/libvmod_directors/automake_boilerplate.am

@@ -15,7 +15,7 @@ vmod_LTLIBRARIES = libvmod_directors.la
 libvmod_directors_la_CFLAGS ?= \
 	@SAN_CFLAGS@
 
-libvmod_directors_la_LDFLAGS ?= \
+libvmod_directors_la_LDFLAGS = \
 	-export-symbols-regex 'Vmod_directors_Data' \
 	$(AM_LDFLAGS) \
 	$(VMOD_LDFLAGS) \

lib/libvmod_proxy/automake_boilerplate.am

@@ -15,7 +15,7 @@ vmod_LTLIBRARIES = libvmod_proxy.la
 libvmod_proxy_la_CFLAGS ?= \
 	@SAN_CFLAGS@
 
-libvmod_proxy_la_LDFLAGS ?= \
+libvmod_proxy_la_LDFLAGS = \
 	-export-symbols-regex 'Vmod_proxy_Data' \
 	$(AM_LDFLAGS) \
 	$(VMOD_LDFLAGS) \

lib/libvmod_purge/automake_boilerplate.am

@@ -15,7 +15,7 @@ vmod_LTLIBRARIES = libvmod_purge.la
 libvmod_purge_la_CFLAGS ?= \
 	@SAN_CFLAGS@
 
-libvmod_purge_la_LDFLAGS ?= \
+libvmod_purge_la_LDFLAGS = \
 	-export-symbols-regex 'Vmod_purge_Data' \
 	$(AM_LDFLAGS) \
 	$(VMOD_LDFLAGS) \

lib/libvmod_std/automake_boilerplate.am

@@ -15,7 +15,7 @@ vmod_LTLIBRARIES = libvmod_std.la
 libvmod_std_la_CFLAGS ?= \
 	@SAN_CFLAGS@
 
-libvmod_std_la_LDFLAGS ?= \
+libvmod_std_la_LDFLAGS = \
 	-export-symbols-regex 'Vmod_std_Data' \
 	$(AM_LDFLAGS) \
 	$(VMOD_LDFLAGS) \

lib/libvmod_unix/automake_boilerplate.am

@@ -15,7 +15,7 @@ vmod_LTLIBRARIES = libvmod_unix.la
 libvmod_unix_la_CFLAGS ?= \
 	@SAN_CFLAGS@
 
-libvmod_unix_la_LDFLAGS ?= \
+libvmod_unix_la_LDFLAGS = \
 	-export-symbols-regex 'Vmod_unix_Data' \
 	$(AM_LDFLAGS) \
 	$(VMOD_LDFLAGS) \

lib/libvmod_vtc/automake_boilerplate.am

@@ -15,7 +15,7 @@ vmod_LTLIBRARIES = libvmod_vtc.la
 libvmod_vtc_la_CFLAGS ?= \
 	@SAN_CFLAGS@
 
-libvmod_vtc_la_LDFLAGS ?= \
+libvmod_vtc_la_LDFLAGS = \
 	-export-symbols-regex 'Vmod_vtc_Data' \
 	$(AM_LDFLAGS) \
 	$(VMOD_LDFLAGS) \