gnu: Add procmail.

* gnu/packages/patches/procmail-ambiguous-getline-debian.patch: New file.
 * gnu-system.am (dist_patch_DATA): Add it.
 * gnu/packages/mail.scm (procmail): New variable.

Signed-off-by: Leo Famulari <leo@famulari.name>

gnu/packages/patches/procmail-ambiguous-getline-debian.patch

@@ -0,0 +1,61 @@
+Rename getline() to procmail_getline() to avoid namespace clash with
+POSIX getline(). Fixes FTBFS.
+
+Copied from Debian:
+http://sources.debian.net/src/procmail/3.22-24/debian/patches/24/
+
+References:
+http://bugs.debian.org/549426
+
+--- a/src/fields.c
++++ b/src/fields.c
+@@ -110,16 +110,16 @@
+ 		    /* try and append one valid field to rdheader from stdin */
+ int readhead P((void))
+ { int idlen;
+-  getline();
++  procmail_getline();
+   if((idlen=breakfield(buf,buffilled))<=0) /* not the start of a valid field */
+      return 0;
+   if(idlen==STRLEN(FROM)&&eqFrom_(buf))			/* it's a From_ line */
+    { if(rdheader)
+ 	return 0;			       /* the From_ line was a fake! */
+-     for(;buflast=='>';getline());	    /* gather continued >From_ lines */
++     for(;buflast=='>';procmail_getline());	    /* gather continued >From_ lines */
+    }
+   else
+-     for(;;getline())		      /* get the rest of the continued field */
++     for(;;procmail_getline())		      /* get the rest of the continued field */
+       { switch(buflast)			     /* will this line be continued? */
+ 	 { case ' ':case '\t':				  /* yep, it sure is */
+ 	      continue;
+--- a/src/formail.c
++++ b/src/formail.c
+@@ -819,7 +819,7 @@
+       { if(split)		       /* gobble up the next start separator */
+ 	 { buffilled=0;
+ #ifdef sMAILBOX_SEPARATOR
+-	   getline();buffilled=0;		 /* but only if it's defined */
++	   procmail_getline();buffilled=0;		 /* but only if it's defined */
+ #endif
+ 	   if(buflast!=EOF)					   /* if any */
+ 	      goto splitit;
+--- a/src/formisc.c
++++ b/src/formisc.c
+@@ -115,7 +115,7 @@
+   buf[buffilled++]=c;
+ }
+ 
+-int getline P((void))			   /* read a newline-terminated line */
++int procmail_getline P((void))			   /* read a newline-terminated line */
+ { if(buflast==EOF)			 /* at the end of our Latin already? */
+    { loadchar('\n');					  /* fake empty line */
+      return EOF;					  /* spread the word */
+--- a/src/formisc.h
++++ b/src/formisc.h
+@@ -17,4 +17,4 @@
+ char*
+  skipwords P((char*start));
+ int
+- getline P((void));
++ procmail_getline P((void));