From 25879fc24d96c89e817e7950ec92d6e2cb41e1b3 Mon Sep 17 00:00:00 2001
From: Pino Toscano <toscano.pino@tiscali.it>
Date: Mon, 14 Dec 2020 20:37:32 +0100
Subject: [PATCH] Basic changes for GNU/Hurd (#676)

* Define OSMINOR & OS_HURD on GNU/Hurd

Add a way to identify GNU/Hurd with b2, and also in the Python support.

* Use /proc/self/exe for executable_path on Hurd

Use the Linux compatibility procfs translator to get the full path of
the current executable.

* Define _GNU_SOURCE on any GNU libc-based OS

Make sure to enable GNU features when building on any OS that uses
GNU libc.
---
 src/engine/jam.cpp     | 2 +-
 src/engine/jam.h       | 4 ++++
 src/engine/sysinfo.cpp | 2 +-
 src/tools/builtin.py   | 6 +++---
 4 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/engine/jam.cpp b/src/engine/jam.cpp
index c419f1fa1..76acdb6f7 100644
--- a/src/engine/jam.cpp
+++ b/src/engine/jam.cpp
@@ -747,7 +747,7 @@ char * executable_path( char const * argv0 )
     sysctl( mib, 4, buf, &size, NULL, 0 );
     return ( !size || size == sizeof( buf ) ) ? NULL : strndup( buf, size );
 }
-#elif defined(__linux__) || defined(__CYGWIN__)
+#elif defined(__linux__) || defined(__CYGWIN__) || defined(__GNU__)
 # include <unistd.h>
 char * executable_path( char const * argv0 )
 {
diff --git a/src/engine/jam.h b/src/engine/jam.h
index 25e5736fd..f9f139582 100644
--- a/src/engine/jam.h
+++ b/src/engine/jam.h
@@ -189,6 +189,10 @@
     #define OSMINOR "OS=DGUX"
     #define OS_DGUX
 #endif
+#ifdef __GNU__
+    #define OSMINOR "OS=HURD"
+    #define OS_HURD
+#endif
 #ifdef __hpux
     #define OSMINOR "OS=HPUX"
     #define OS_HPUX
diff --git a/src/engine/sysinfo.cpp b/src/engine/sysinfo.cpp
index c3257e71e..fa2e3c163 100644
--- a/src/engine/sysinfo.cpp
+++ b/src/engine/sysinfo.cpp
@@ -18,7 +18,7 @@
 #include <unistd.h>
 #endif
 
-#if defined(OS_LINUX)
+#if defined(OS_LINUX) || defined(__GLIBC__)
 // Need to define this in case it's not as that's the only way to get the
 // sched_* APIs.
 #ifndef _GNU_SOURCE
diff --git a/src/tools/builtin.py b/src/tools/builtin.py
index 9eeaaf697..ecec2c9e3 100644
--- a/src/tools/builtin.py
+++ b/src/tools/builtin.py
@@ -82,9 +82,9 @@ def variant (name, parents_or_properties, explicit_properties = []):
     feature.compose ("<variant>" + name, explicit_properties.all())
 
 __os_names = """
-    amiga aix appletv bsd cygwin darwin dos emx freebsd hpux iphone linux netbsd
-    openbsd osf qnx qnxnto sgi solaris sun sunos svr4 sysv ultrix unix unixware
-    vms windows
+    amiga aix appletv bsd cygwin darwin dos emx freebsd hpux hurd iphone linux
+    netbsd openbsd osf qnx qnxnto sgi solaris sun sunos svr4 sysv ultrix unix
+    unixware vms windows
 """.split()
 
 # Translates from bjam current OS to the os tags used in host-os and target-os,