[openwrt/openwrt] ppp: compile fix: unset FILTER variable in Makefile

[LEDE Commits]

hauke pushed a commit to openwrt/openwrt.git, branch openwrt-21.02:
https://git.openwrt.org/b89accdfbc771e9936abf33dd5cfcd6882841564

commit b89accdfbc771e9936abf33dd5cfcd6882841564
Author: Eike Ritter <git at rittere.co.uk>
AuthorDate: Sun Mar 14 18:50:21 2021 +0000

    ppp: compile fix: unset FILTER variable in Makefile
    
    If the environment variable FILTER is set before compilation,
    compilation of the ppp-package will fail with the error message
    
    Package ppp is missing dependencies for the following libraries:
    libpcap.so.1
    
    The reason is that the OpenWrt-patch for the Makefile only comments
    out the line FILTER=y. Hence the pcap-library will be dynamically
    linked if the environment variable FILTER is set elsewhere, which
    causes compilation to fail. The fix consists on explicitly unsetting
    the variable FILTER instead.
    
    Signed-off-by: Eike Ritter <git at rittere.co.uk>
    (cherry picked from commit 46cd0765d0c585dc0b48c8c0a3f116ef83cd580f)
---
 .../network/services/ppp/patches/610-pppd_compile_fix.patch  | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/package/network/services/ppp/patches/610-pppd_compile_fix.patch b/package/network/services/ppp/patches/610-pppd_compile_fix.patch
new file mode 100644
index 0000000000..474f11832a
--- /dev/null
+++ b/package/network/services/ppp/patches/610-pppd_compile_fix.patch
@@ -0,0 +1,12 @@
+--- a/pppd/Makefile.linux
++++ b/pppd/Makefile.linux
+@@ -48,7 +48,8 @@ MPPE=y
+ # Uncomment the next line to include support for PPP packet filtering.
+ # This requires that the libpcap library and headers be installed
+ # and that the kernel driver support PPP packet filtering.
+-#FILTER=y
++# libpcap statically linked in OpenWRT, hence disabled here.
++FILTER=
+ 
+ # Support for precompiled filters
+ PRECOMPILED_FILTER=y