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# Require secp256k1 of at least version 0.1.0.19 and output ${secp256k1_CPPFLAGS/LIBS/PKG}.
#------------------------------------------------------------------------------
PKG_CHECK_MODULES([secp256k1], [libsecp256k1 >= 0.1.0.19],
[secp256k1_INCLUDEDIR="`$PKG_CONFIG --variable=includedir "libsecp256k1 >= 0.1.0.19" 2>/dev/null`"
secp256k1_OTHER_CFLAGS="`$PKG_CONFIG --cflags-only-other "libsecp256k1 >= 0.1.0.19" 2>/dev/null`"],
[AC_MSG_ERROR([libsecp256k1 >= 0.1.0.19 is required but was not found.])])
AC_SUBST([secp256k1_PKG], ['libsecp256k1 >= 0.1.0.19'])
AC_SUBST([secp256k1_CPPFLAGS], [${secp256k1_CFLAGS}])
AS_IF([test x${secp256k1_INCLUDEDIR} != "x"],
[AC_SUBST([secp256k1_ISYS_CPPFLAGS], ["-isystem${secp256k1_INCLUDEDIR} ${secp256k1_OTHER_CFLAGS}"])],
[AC_SUBST([secp256k1_ISYS_CPPFLAGS], [${secp256k1_OTHER_CFLAGS}])])
AC_MSG_NOTICE([secp256k1_CPPFLAGS : ${secp256k1_CPPFLAGS}])
AC_MSG_NOTICE([secp256k1_ISYS_CPPFLAGS : ${secp256k1_ISYS_CPPFLAGS}])
AC_MSG_NOTICE([secp256k1_OTHER_CFLAGS : ${secp256k1_OTHER_CFLAGS}])
AC_MSG_NOTICE([secp256k1_INCLUDEDIR : ${secp256k1_INCLUDEDIR}])
AC_MSG_NOTICE([secp256k1_LIBS : ${secp256k1_LIBS}])
AS_CASE([${enable_isystem}],[yes],
[AC_SUBST([secp256k1_BUILD_CPPFLAGS], [${secp256k1_ISYS_CPPFLAGS}])],
[AC_SUBST([secp256k1_BUILD_CPPFLAGS], [${secp256k1_CPPFLAGS}])])
AC_MSG_NOTICE([secp256k1_BUILD_CPPFLAGS : ${secp256k1_BUILD_CPPFLAGS}])