Use autoconf/automake to configure and make ppp

[ppp.git] / m4 / ax_check_pcap.m4

diff --git a/m4/ax_check_pcap.m4 b/m4/ax_check_pcap.m4
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+++ b/m4/ax_check_pcap.m4
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+# SYNOPSIS
+#
+#   AX_CHECK_PCAP([action-if-found[, action-if-not-found]]
+#
+# DESCRIPTION
+#
+#   Look for libpcap in a number of default locations, or in a provided location
+#   (via --with-pcap=). Sets
+#       PCAP_CFLAGS
+#       PCAP_LDFLAGS
+#       PCAP_LIBS
+#
+#   and calls ACTION-IF-FOUND or ACTION-IF-NOT-FOUND appropriately
+#
+# LICENSE
+#
+#   Copyright (c) 2021 Eivind Naess <eivnaes@yahoo.com>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 1
+
+AC_DEFUN([AX_CHECK_PCAP], [
+    AC_ARG_WITH([pcap],
+        [AS_HELP_STRING([--with-pcap=DIR],
+            [With libpcap support, see https://www.tcpdump.org])],
+        [
+            case "$withval" in
+            "" | y | ye | yes)
+                pcapdirs="/usr/local /usr/lib /usr"  
+              ;;
+            n | no)
+                with_pcap="no"
+              ;;
+            *)
+                pcapdirs="$withval"
+              ;;
+            esac
+        ])
+    
+    if [ test "${with_pcap}" != "no" ] ; then
+        PCAP_LIBS="-lpcap"
+        for pcapdir in $pcapdirs; do
+            AC_MSG_CHECKING([for pcap.h in $pcapdir])
+            if test -f "$pcapdir/include/pcap.h"; then
+                PCAP_CFLAGS="-I$pcapdir/include"
+                PCAP_LDFLAGS="-L$pcapdir/lib"
+                AC_MSG_RESULT([yes])
+                break
+            else
+                AC_MSG_RESULT([no])
+            fi
+        done
+
+        # try the preprocessor and linker with our new flags,
+        # being careful not to pollute the global LIBS, LDFLAGS, and CPPFLAGS
+
+        AC_MSG_CHECKING([if compiling and linking against libpcap works])
+
+        save_LIBS="$LIBS"
+        save_LDFLAGS="$LDFLAGS"
+        save_CPPFLAGS="$CPPFLAGS"
+        LDFLAGS="$PCAP_LDFLAGS $LDFLAGS"
+        LIBS="$PCAP_LIBS $LIBS"
+        CPPFLAGS="$PCAP_CFLAGS $CPPFLAGS"
+        AC_LINK_IFELSE(
+            [AC_LANG_PROGRAM(
+                [@%:@include <pcap.h>],
+                [pcap_create(0,0);])],
+            [
+                AC_MSG_RESULT([yes])
+                with_pcap=yes
+                $1
+            ], [
+                AC_MSG_RESULT([no])
+                with_pcap=""
+                $2
+            ])
+        CPPFLAGS="$save_CPPFLAGS"
+        LDFLAGS="$save_LDFLAGS"
+        LIBS="$save_LIBS"
+
+        AC_SUBST([PCAP_CFLAGS])
+        AC_SUBST([PCAP_LIBS])
+        AC_SUBST([PCAP_LDFLAGS])
+    fi
+
+    AM_CONDITIONAL(WITH_PCAP, test -n "${with_pcap}")
+])
+