I don't know why this version is no longer in the kernel.org FTP archives, but you can pull it from git:
$ git clone git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git
$ cd linux-stable
$ git checkout -f v188.8.131.52
$ head -4 Makefile
VERSION = 2
PATCHLEVEL = 6
SUBLEVEL = 26
EXTRAVERSION = .5
I needed the
-f option in the
checkout command here for reasons I cannot figure out. It claims that — immediately after the
clone — I have local modifications to my tree, and it's trying to save me from throwing them away by switching branches. Bizarre.
Annnyway... Building against generic 2.6.26 headers probably isn't a problem. The changes are likely things which affect kernel functionality but not any APIs. Thus, the generic headers will export the same APIs.
If you're running a kernel with changes made by your embedded Linux distro provider, those should not affect any ABIs. The main thing you need to do to get the correct ABI is use the correct cross-compilation toolchain.