build: Create .la library for crc32c

Libtool will yell at you if you try to link a shared library against
static ones.

This change creates a libtool archive library for crc32c and allows a
shared library to be linked against it portably.

Also specify -static in both:

- ..._la_CXXFLAGS so that libtool will avoid building two versions of
  each object (one PIC, one non-PIC). We just need the one that is
  suitable for static linking.
- ..._la_LDFLAGS so that libtool will create a static library.

[META] This change is done in preparation for a future commit where we
       link the libbitcoinkernel library against this one.

Author: dongcarl

src/Makefile.crc32c.include

@@ -2,9 +2,9 @@
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-LIBCRC32C_INT = crc32c/libcrc32c.a
+LIBCRC32C_INT = crc32c/libcrc32c.la
 
-EXTRA_LIBRARIES += $(LIBCRC32C_INT)
+noinst_LTLIBRARIES += $(LIBCRC32C_INT)
 
 LIBCRC32C = $(LIBCRC32C_INT)
 
@@ -33,41 +33,49 @@ else
 CRC32C_CPPFLAGS_INT += -DBYTE_ORDER_BIG_ENDIAN=0
 endif
 
-crc32c_libcrc32c_a_CPPFLAGS = $(AM_CPPFLAGS) $(CRC32C_CPPFLAGS_INT) $(CRC32C_CPPFLAGS)
-crc32c_libcrc32c_a_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
-
-crc32c_libcrc32c_a_SOURCES =
-crc32c_libcrc32c_a_SOURCES += crc32c/include/crc32c/crc32c.h
-crc32c_libcrc32c_a_SOURCES += crc32c/src/crc32c_arm64.h
-crc32c_libcrc32c_a_SOURCES += crc32c/src/crc32c_arm64_check.h
-crc32c_libcrc32c_a_SOURCES += crc32c/src/crc32c_internal.h
-crc32c_libcrc32c_a_SOURCES += crc32c/src/crc32c_prefetch.h
-crc32c_libcrc32c_a_SOURCES += crc32c/src/crc32c_read_le.h
-crc32c_libcrc32c_a_SOURCES += crc32c/src/crc32c_round_up.h
-crc32c_libcrc32c_a_SOURCES += crc32c/src/crc32c_sse42_check.h
-crc32c_libcrc32c_a_SOURCES += crc32c/src/crc32c_sse42.h
-
-crc32c_libcrc32c_a_SOURCES += crc32c/src/crc32c.cc
-crc32c_libcrc32c_a_SOURCES += crc32c/src/crc32c_portable.cc
+crc32c_libcrc32c_la_CPPFLAGS = $(AM_CPPFLAGS) $(CRC32C_CPPFLAGS_INT) $(CRC32C_CPPFLAGS)
+
+# Specify -static in both CXXFLAGS and LDFLAGS so libtool will only build a
+# static version of this library. We don't need a dynamic version, and a dynamic
+# version can't be used on windows anyway because the library doesn't currently
+# export DLL symbols.
+crc32c_libcrc32c_la_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS) -static
+crc32c_libcrc32c_la_LDFLAGS = $(AM_LDFLAGS) -static
+
+crc32c_libcrc32c_la_SOURCES =
+crc32c_libcrc32c_la_SOURCES += crc32c/include/crc32c/crc32c.h
+crc32c_libcrc32c_la_SOURCES += crc32c/src/crc32c_arm64.h
+crc32c_libcrc32c_la_SOURCES += crc32c/src/crc32c_arm64_check.h
+crc32c_libcrc32c_la_SOURCES += crc32c/src/crc32c_internal.h
+crc32c_libcrc32c_la_SOURCES += crc32c/src/crc32c_prefetch.h
+crc32c_libcrc32c_la_SOURCES += crc32c/src/crc32c_read_le.h
+crc32c_libcrc32c_la_SOURCES += crc32c/src/crc32c_round_up.h
+crc32c_libcrc32c_la_SOURCES += crc32c/src/crc32c_sse42_check.h
+crc32c_libcrc32c_la_SOURCES += crc32c/src/crc32c_sse42.h
+
+crc32c_libcrc32c_la_SOURCES += crc32c/src/crc32c.cc
+crc32c_libcrc32c_la_SOURCES += crc32c/src/crc32c_portable.cc
 
 if ENABLE_SSE42
-LIBCRC32C_SSE42_INT = crc32c/libcrc32c_sse42.a
-EXTRA_LIBRARIES += $(LIBCRC32C_SSE42_INT)
+LIBCRC32C_SSE42_INT = crc32c/libcrc32c_sse42.la
+noinst_LTLIBRARIES += $(LIBCRC32C_SSE42_INT)
 LIBCRC32C += $(LIBCRC32C_SSE42_INT)
 
-crc32c_libcrc32c_sse42_a_CPPFLAGS = $(crc32c_libcrc32c_a_CPPFLAGS)
-crc32c_libcrc32c_sse42_a_CXXFLAGS = $(crc32c_libcrc32c_a_CXXFLAGS) $(SSE42_CXXFLAGS)
+crc32c_libcrc32c_sse42_la_CPPFLAGS = $(crc32c_libcrc32c_la_CPPFLAGS)
+crc32c_libcrc32c_sse42_la_CXXFLAGS = $(crc32c_libcrc32c_la_CXXFLAGS) $(SSE42_CXXFLAGS)
+crc32c_libcrc32c_sse42_la_LDFLAGS = $(crc32c_libcrc32c_la_LDFLAGS)
 
-crc32c_libcrc32c_sse42_a_SOURCES = crc32c/src/crc32c_sse42.cc
+crc32c_libcrc32c_sse42_la_SOURCES = crc32c/src/crc32c_sse42.cc
 endif
 
 if ENABLE_ARM_CRC
-LIBCRC32C_ARM_CRC_INT = crc32c/libcrc32c_arm_crc.a
-EXTRA_LIBRARIES += $(LIBCRC32C_ARM_CRC_INT)
+LIBCRC32C_ARM_CRC_INT = crc32c/libcrc32c_arm_crc.la
+noinst_LTLIBRARIES += $(LIBCRC32C_ARM_CRC_INT)
 LIBCRC32C += $(LIBCRC32C_ARM_CRC_INT)
 
-crc32c_libcrc32c_arm_crc_a_CPPFLAGS = $(crc32c_libcrc32c_a_CPPFLAGS)
-crc32c_libcrc32c_arm_crc_a_CXXFLAGS = $(crc32c_libcrc32c_a_CXXFLAGS) $(ARM_CRC_CXXFLAGS)
+crc32c_libcrc32c_arm_crc_la_CPPFLAGS = $(crc32c_libcrc32c_la_CPPFLAGS)
+crc32c_libcrc32c_arm_crc_la_CXXFLAGS = $(crc32c_libcrc32c_la_CXXFLAGS) $(ARM_CRC_CXXFLAGS)
+crc32c_libcrc32c_arm_crc_la_LDFLAGS = $(crc32c_libcrc32c_la_LDFLAGS)
 
-crc32c_libcrc32c_arm_crc_a_SOURCES = crc32c/src/crc32c_arm64.cc
+crc32c_libcrc32c_arm_crc_la_SOURCES = crc32c/src/crc32c_arm64.cc
 endif