libbitcoinconsensus: Add pkg-config support

Makefile.am

@@ -4,6 +4,11 @@ SUBDIRS = src
 
 GZIP_ENV="-9n"
 
+if BUILD_BITCOIN_LIBS
+pkgconfigdir = $(libdir)/pkgconfig
+pkgconfig_DATA = libbitcoinconsensus.pc
+endif
+
 BITCOIND_BIN=$(top_builddir)/src/bitcoind$(EXEEXT)
 BITCOIN_QT_BIN=$(top_builddir)/src/qt/bitcoin-qt$(EXEEXT)
 BITCOIN_CLI_BIN=$(top_builddir)/src/bitcoin-cli$(EXEEXT)

configure.ac

@@ -680,6 +680,7 @@ AC_MSG_CHECKING([whether to build libraries])
 AM_CONDITIONAL([BUILD_BITCOIN_LIBS], [test x$build_bitcoin_libs = xyes])
 if test x$build_bitcoin_libs = xyes; then
   AC_DEFINE(HAVE_CONSENSUS_LIB, 1, [Define this symbol if the consensus lib has been built])
+  AC_CONFIG_FILES([libbitcoinconsensus.pc:libbitcoinconsensus.pc.in])
 fi
 AC_MSG_RESULT($build_bitcoin_libs)
 

libbitcoinconsensus.pc.in

@@ -0,0 +1,11 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: Bitcoin Core consensus library
+Description: Library for the Bitcoin consensus protocol.
+Version: @PACKAGE_VERSION@
+Libs: -L${libdir} -lbitcoinconsensus
+Cflags: -I${includedir}
+Requires.private: libcrypto