Add build information to README.

README.md

@@ -41,3 +41,4 @@ The only functions not available are the commands to save or load the partition
 - EFI is UTF-16 while util-linux fdisk uses UTF-8 internally and the original glue functions hand code conversions from UTF-8 to UTF-16. This process has been extended with Davipb's [UTF-8/UTF-16 converter](https://github.com/Davipb/utf8-utf16-converter) when processing command line arguments.
 - For all the system calls from the standard libray we build EFI versions of functions like write(), read() and so on, all these functions are in the ".c" source files in this "." directory, not in the "libmy" subdirectory.
 - If you change options in the Makefile (like enable asserts or stack checking or _FORTIFY_SOURCE or EFI_DEBUG debugging) the link should warn you that you're adding bloat to the program.
+- The current build environment supports GCC-12 and glibc v2.39 running under Ubuntu 24.04 LTS with util-linux fdisk versions up to 2.40.2. When building under other Linux distributions check your environment for compatibility.