= Common tasks and useful tips for porting Unix software to OS/2 =

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This page explains some common code changes often necessary to make Unix software work properly on OS/2. These changes are mainly related to various components shared among Unix programs. These changes are tracked here since we don't normally push upstream and hence we should apply them in each new project that we port and that uses these components.

== Common tasks ==

=== Fix POTFILES generation ===

The fix is applied to `po.m4` that creates rules for `POTFILES` generation. Unfortunately, the upstream version doesn't take DOS drive letters into account and hence creates incorrect relative paths in the generated `POTFILES` file (like `../D:/Coding/myproject/trunk/...`). Here is a typical fix: r1009. When applied, `configure` and friends need to be regenerated in the source tree and then `configure` needs to be re-run to generate proper `Makefile`s.

=== Fix HAVE_ICONV detection ===

The fix is applied to `iconv.m4` that detects if the `HAVE_ICONV` config.h macro should be set or not. Here is a typical fix: r1023 (originally this: r934). When applied, `configure` and friends need to be regenerated in the source tree and then `configure` needs to be re-run to generate a proper `config.h`.

=== Fix EOLs in git-version-gen ===

Some projects use the `build-aux/git-version-gen` script to define the project version in `configure.ac`. The "stock" version of this script doesn't understand CRLF as line terminators which leads to a corrupt `configure`. The fix is rather simple and can be seen here: r968.

=== Fix OS/2 DLL name in libtool ===

When `libtool` is used to generate project DLLs, such a DLL often gets a version number in its name (e.g. `libpixman-1.so.0`, where `pixman-1` is the  base DLL name and `0` is the major version number). However, on OS/2 the version information cannot follow the extension and hence it must be put into the name part. But the name part is limited to 8 chars so `libtool` has to cut the base DLL name by default to make the appended major version number fit the limit. In case of the `pixman` this would give us `pixman-0.dll` which looks misleading (the correct name is `pixman10.dll` in this case).

A proper solution here is to force `libtool` use a special, short version of the base name for the DLL file (and only for it — all other files, such as the import library name, should carry the original name so that the linker can find it). This is done using the `-shortname` libtool option. Where to add it varies from project to project but the typical place is the _la_LDFLAGS variable in `Makefile.am` for the library. See r1232 for a real-life example.