Add support for building on OpenBSD (#471)

README.md

@@ -105,6 +105,19 @@ You need to install the following packages using brew (or a package manager of y
 
 	brew install autoconf automake libtool openssl wget
 
+### Install dependencies for OpenBSD
+
+You need to install the following packages using pkg_add:
+
+	pkg_add automake libtool
+
+On OpenBSD you have to explicitly set the environment variables `AUTOCONF_VERSION` and 
+`AUTOMAKE_VERSION` to a version installed on your system.
+
+	export AUTOCONF_VERSION=`ls -1 /usr/local/bin/autoreconf-* | sort | tail -n 1 | cut -d'-' -f2`
+	export AUTOMAKE_VERSION=`ls -1 /usr/local/bin/automake-* | sort | tail -n 1 | cut -d'-' -f2`
+
+
 ### Building
 
 To build, first clone or download the source from GitHub:

config/detect_host_and_cpu.m4

@@ -16,6 +16,9 @@ AC_DEFUN([DETECT_HOST_AND_CPU], [
     linux*)
           linux=true
           ;;
+    openbsd*)
+          openbsd=true
+          ;;
       *)
           #Default Case
           AC_MSG_ERROR([Your platform is not currently supported])
@@ -24,6 +27,7 @@ AC_DEFUN([DETECT_HOST_AND_CPU], [
 
   AM_CONDITIONAL([ON_DARWIN], [test "x$darwin" = xtrue])
   AM_CONDITIONAL([ON_LINUX], [test "x$linux" = xtrue])
+  AM_CONDITIONAL([ON_OPENBSD], [test "x$openbsd" = xtrue])
 
   # Enable assembly optimizations here
   # Appearenly asm optimizations do not work well with darwin

src/sig/picnic/external/endian_compat.h

@@ -59,11 +59,17 @@ static inline uint64_t AATR_CONST bswap64(uint64_t x) {
 #endif
 #endif
 
-/* OS X / OpenBSD */
-#if defined(__APPLE__) || defined(__OpenBSD__)
+/* OS X */
+#if defined(__APPLE__)
 #include <machine/endian.h>
 #endif
 
+/* OpenBSD */
+#if defined(__OpenBSD__)
+#include <machine/endian.h>
+#define HAVE_HOSTSWAP
+#endif
+
 /* other BSDs */
 #if defined(__FreeBSD__) || defined(__NETBSD__) || defined(__NetBSD__)
 #include <sys/endian.h>