message: build: Improve error message when pkg-config is not installed
diff: @@ -18,7 +18,7 @@ AC_CONFIG_HEADERS([src/config/bitcoin-config.h])
  AC_CONFIG_AUX_DIR([build-aux])
  AC_CONFIG_MACRO_DIR([build-aux/m4])
  -m4_ifndef([PKG_PROG_PKG_CONFIG], [AC_MSG_ERROR([PKG_PROG_PKG_CONFIG macro not found. Please install pkg-config and re-run autogen.sh])])
  +m4_ifndef([PKG_PROG_PKG_CONFIG], [m4_fatal([PKG_PROG_PKG_CONFIG macro not found. Please install pkg-config and re-run autogen.sh])])
  PKG_PROG_PKG_CONFIG
  if test "$PKG_CONFIG" = ""; then
  AC_MSG_ERROR([pkg-config not found])
  