build: Drop redundant AC_SUBST macros

Variables that are declared with AC_ARG_VAR macro are substituted via
AC_SUBST macro.
PKG_CHECK_MODULES macro already has AC_ARG_VAR(${PACKAGE}_CFLAGS) and
AC_ARG_VAR(${PACKAGE}_LIBS).

Author: hebasto

build-aux/m4/bitcoin_find_bdb48.m4

@@ -91,7 +91,6 @@ AC_DEFUN([BITCOIN_FIND_BDB48],[
     fi
   fi
   if test "$use_bdb" != "no"; then
-    AC_SUBST(BDB_LIBS)
     AC_DEFINE([USE_BDB], [1], [Define if BDB support should be compiled in])
     use_bdb=yes
   fi

build-aux/m4/bitcoin_qt.m4

@@ -278,9 +278,7 @@ AC_DEFUN([BITCOIN_QT_CONFIGURE],[
   AC_SUBST(QT_LIBS)
   AC_SUBST(QT_LDFLAGS)
   AC_SUBST(QT_DBUS_INCLUDES)
-  AC_SUBST(QT_DBUS_LIBS)
   AC_SUBST(QT_TEST_INCLUDES)
-  AC_SUBST(QT_TEST_LIBS)
   AC_SUBST(QT_SELECT, qt5)
   AC_SUBST(MOC_DEFS)
 ])

configure.ac

@@ -1542,8 +1542,6 @@ if test "$with_libmultiprocess" = "yes" || test "$with_libmultiprocess" = "auto"
 elif test "$with_libmultiprocess" != "no"; then
   AC_MSG_ERROR([--with-libmultiprocess=$with_libmultiprocess value is not yes, auto, or no])
 fi
-AC_SUBST(LIBMULTIPROCESS_CFLAGS)
-AC_SUBST(LIBMULTIPROCESS_LIBS)
 
 dnl Enable multiprocess check
 
@@ -1846,16 +1844,11 @@ AC_SUBST(ENABLE_EXTERNAL_SIGNER)
 AC_SUBST(USE_UPNP)
 AC_SUBST(USE_QRCODE)
 AC_SUBST(BOOST_LIBS)
-AC_SUBST(SQLITE_LIBS)
 AC_SUBST(TESTDEFS)
 AC_SUBST(MINIUPNPC_CPPFLAGS)
 AC_SUBST(MINIUPNPC_LIBS)
 AC_SUBST(NATPMP_CPPFLAGS)
 AC_SUBST(NATPMP_LIBS)
-AC_SUBST(EVENT_LIBS)
-AC_SUBST(EVENT_PTHREADS_LIBS)
-AC_SUBST(ZMQ_LIBS)
-AC_SUBST(QR_LIBS)
 AC_SUBST(HAVE_GMTIME_R)
 AC_SUBST(HAVE_FDATASYNC)
 AC_SUBST(HAVE_FULLFSYNC)