Do not build 32bit skeletons lib and check-converter

when the 32bit build is dislabed.

On MacOS with Xcode 9.0 the make check fails because the ar
cannot build empty static libraries

Fixes #228

skeletons/Makefile.am

@@ -20,13 +20,13 @@ uninstall-local:
 
 check_LTLIBRARIES =             \
     libasn1cskeletons.la        \
-    libasn1cskeletons_c89.la    \
-    libasn1cskeletons_c89_32.la
+    libasn1cskeletons_c89.la
 
 libasn1cskeletons_c89_la_CFLAGS = $(SKELETONS_CFLAGS)
 libasn1cskeletons_c89_la_SOURCES = $(libasn1cskeletons_la_SOURCES)
 
 if EXPLICIT_M32
+check_LTLIBRARIES += libasn1cskeletons_c89_32.la
 libasn1cskeletons_c89_32_la_CFLAGS = $(SKELETONS_CFLAGS) $(CFLAGS_M32) -Wno-format
 libasn1cskeletons_c89_32_la_SOURCES = $(libasn1cskeletons_la_SOURCES)
 endif
@@ -103,8 +103,7 @@ libasn1cskeletons_la_SOURCES =                  \
 
 check_PROGRAMS =                    \
     check-converter_example         \
-    check-converter_c89_example     \
-    check-converter_c89_32_example
+    check-converter_c89_example
 LDADD = -lm
 
 check_converter_example_CFLAGS = -DNO_ASN_PDU
@@ -115,7 +114,10 @@ check_converter_c89_example_CFLAGS = $(SKELETON_CFLAGS) -DNO_ASN_PDU
 check_converter_c89_example_SOURCES = converter-example.c
 check_converter_c89_example_LDADD = libasn1cskeletons_c89.la
 
+if EXPLICIT_M32
+check_PROGRAMS += check-converter_c89_32_example
 check_converter_c89_32_example_CFLAGS = $(SKELETON_CFLAGS) $(CFLAGS_M32) -DNO_ASN_PDU
 check_converter_c89_32_example_SOURCES = converter-example.c
 check_converter_c89_32_example_LDADD = libasn1cskeletons_c89_32.la
+endif