ppp: fix build with glibc>=2.28

pkgs/tools/networking/ppp/default.nix

@@ -10,10 +10,17 @@ stdenv.mkDerivation rec {
   };
 
   patches =
-    [ ( substituteAll {
+    [
+      # fix for glibc>=2.28
+      (fetchurl {
+        url = "https://github.com/paulusmack/ppp/commit/3c7b86229f7bd2600d74db14b1fe5b3896be3875.patch";
+        sha256 = "0qlbi247lx3injpy8a1gcij9yilik0vfaibkpvdp88k3sa1rs69z";
+      })
+      ( substituteAll {
         src = ./nix-purity.patch;
         inherit libpcap;
         glibc = stdenv.cc.libc.dev or stdenv.cc.libc;
+        openssl = openssl.dev;
       })
       # Without nonpriv.patch, pppd --version doesn't work when not run as
       # root.

pkgs/tools/networking/ppp/nix-purity.patch

@@ -1,8 +1,8 @@
 diff --git a/pppd/Makefile.linux b/pppd/Makefile.linux
-index 060db6a..c151c62 100644
+index 1ebebec..bf90c62 100644
 --- a/pppd/Makefile.linux
 +++ b/pppd/Makefile.linux
-@@ -117,7 +117,7 @@ CFLAGS   += -DHAS_SHADOW
+@@ -120,7 +120,7 @@ CFLAGS   += -DHAS_SHADOW
  #LIBS     += -lshadow $(LIBS)
  endif
  
@@ -11,7 +11,16 @@ index 060db6a..c151c62 100644
  CFLAGS  += -DHAVE_CRYPT_H=1
  LIBS	+= -lcrypt
  endif
-@@ -169,7 +169,7 @@ LIBS	+= -ldl
+@@ -132,7 +132,7 @@ endif
+ 
+ ifdef NEEDDES
+ ifndef USE_CRYPT
+-CFLAGS   += -I/usr/include/openssl
++CFLAGS   += -I@openssl@/include/openssl
+ LIBS     += -lcrypto
+ else
+ CFLAGS   += -DUSE_CRYPT=1
+@@ -178,7 +178,7 @@ LIBS	+= -ldl
  endif
  
  ifdef FILTER