# Building gnatlib
**URL:** https://forum.ada-lang.io/t/building-gnatlib/4751
**Category:** Help
**Tags:** gnat
**Created:** [September 18, 2026, 3:48pm UTC](https://forum.ada-lang.io/t/building-gnatlib/4751 "2026-09-18T15:48:20Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@PeterBB](https://forum.ada-lang.io/u/PeterBB)
#### Post date: [September 18, 2026, 3:48pm UTC](https://forum.ada-lang.io/t/building-gnatlib/4751/1 "2026-09-18T15:48:20Z")
Is there any way to do a stand alone build of
lingnarl and libgnat without building the whole of gcc?
I’ve tried the following,
`mkdir build && cd build`
`../gcc/configure --enable-languages=ada`
`cd ada`
`make gnatlib`
but it fails with
`raised raised ADA.IO_EXCEPTIONS.NAME_ERROR : s-oscons-tmplt.s: No such file or directory`
(having previously issued `rm -f rts/s-oscons-tmplt.i rts/s-oscons-tmplt.s`
---
### Author:  [@OneWingedShark](https://forum.ada-lang.io/u/OneWingedShark)
#### Post date: [September 18, 2026, 4:09pm UTC](https://forum.ada-lang.io/t/building-gnatlib/4751/3 "2026-09-18T16:09:12Z")
That looks like a missing file or directory to me.
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### Author:  [@PeterBB](https://forum.ada-lang.io/u/PeterBB)
#### Post date: [September 18, 2026, 5:12pm UTC](https://forum.ada-lang.io/t/building-gnatlib/4751/4 "2026-09-18T17:12:09Z")
Looks like the immediate cause of the first fail, is that the generated Makefile uses a variable,
$GCC\_FOR\_TARGET which is undefined when used. Hence errors such as;
`/bin/bash: line 2: -W: command not found`
`/bin/bash: line 3: -W: command not found`
because the command should have been gcc -W etc, not just -W.
Defining GCC\_FOR\_TARGET, the build gets a bit farther,
then fails because tconfig.h is missing. I understand that file should be created
by configure, but is not.
`adaint.c:129:10: fatal error: tconfig.h: No such file or directory`
---
### Author:  [@AdaOrbit](https://forum.ada-lang.io/u/AdaOrbit)
#### Post date: [September 18, 2026, 5:13pm UTC](https://forum.ada-lang.io/t/building-gnatlib/4751/5 "2026-09-18T17:13:18Z")
run `gnatls -v`
under “source path” is where your systems rts is. For me it’s `/usr/lib/gcc/x86_64-pc-linux-gnu/15/adainclude`. If you don’t have gnat but gcc with Ada support you can also run `gcc -print-file-name=adainclude` to get the path.
You can now build it yourself using by compiling it using `-gnatg` but I’m not sure if that will work on your system.
If you have the gcc source code you can just use libada.gpr. I haven’t tried that tho. See:
> **[Rebuilding the GNAT Run-Time Library (GNAT User’s Guide for Native Platforms)](https://gcc.gnu.org/onlinedocs/gcc-15.3.0/gnat_ugn/Rebuilding-the-GNAT-Run-Time-Library.html)**
>
> Rebuilding the GNAT Run-Time Library (GNAT User’s Guide for Native Platforms)
`https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/ada/libgnat/libada.gpr;h=2848c566ee10cdf5844786fd433d75175510726d;hb=refs/heads/master`
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### Author:  [@PeterBB](https://forum.ada-lang.io/u/PeterBB)
#### Post date: [September 18, 2026, 7:26pm UTC](https://forum.ada-lang.io/t/building-gnatlib/4751/6 "2026-09-18T19:26:51Z")
Success, Thanks!! 😀
I’m building using gcc source. After the configure step I described above,
this is what I did.
```ada
cd ada/rts
mkdir rts-debug
cp rts-debug
cp -a gprls -v | grep adainclude .
cp -a -v ../../*.c .
cp -a -v ../../*.h .
```
(Copied in unwind-pe.h from libgcc)
`gprbuild -p -Plibada -j0 -XCFLAGS="-O2 -g" -XADAFLAGS="-gnatn"`
I think the key bit I was missing, was all the gprbuild switches.
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### Author:  [@system](https://forum.ada-lang.io/u/system)
#### Post date: [September 19, 2026, 7:27pm UTC](https://forum.ada-lang.io/t/building-gnatlib/4751/7 "2026-09-19T19:27:13Z")
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