The autoconf info pages say ‘dirname’ Not all hosts have a working ‘dirname’, and you should instead use ‘AS_DIRNAME’ (*note Programming in M4sh::). [...]
Looking into the git repository log it seems this remark is oooold, essentially written before 1996. I now wonder whether this has any relevance today. Are there still platforms supported by autoconf that don't have `dirname`? My question arises from the fact that I often look up the autoconf info pages to check whether certain common tools are portable or not in shell scripts. However, in this particular case it seems to me that the advice, while useful for autoconf, is very outdated. Werner