miscmods: don't directly use `ld`

Avoid using ld directly.  It is done purposely in this case to
apparently work around some issues with Solaris linker.  While we could
resolve it here by simply using $LD, use the compiler as the commented
out original would, for it is even better.

Bug: https://bugs.gentoo.org/976375
Signed-off-by: Fabian Groffen <grobian@bitzolder.nl>

--- a/src/miscmods/Makefile
+++ b/src/miscmods/Makefile
@@ -62,7 +62,7 @@
 	$(FE)$(CC) -c $(CFLAGS) $(INCLUDE) pdkim.c
 	$(FE)$(CC) -c $(CFLAGS) $(INCLUDE) $(TLS_INCLUDE) signing.c
 	$(FE)mv dkim.o dkim_tmp.o
-	$(FE)ld -r -o dkim.o $(LDFLAGS_PARTIAL) \
+	$(FE)$(CC) -r -o dkim.o $(LDFLAGS_PARTIAL) \
 		dkim_tmp.o dkim_transport.o pdkim.o signing.o
 
 # Similarly, we want a single .so for the dynamic-load module