docs: advise against HP-UX make due to time stamp semantics.

* doc/autoconf.texi (Timestamps and Make): Document HP-UX 11.31
make issue with targets having the same time stamps as their
prerequisites.
* doc/install.texi (Particular Systems): Warn against using
HP-UX make.

Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>

diff --git a/ChangeLog b/ChangeLog
index 0d7f12d4a213a4b473f7e0415711a4f77afe2458..a302c5d17650d03e1beaea50b08077249cbed6ef 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2011-01-25  Ralf Wildenhues  <Ralf.Wildenhues@gmx.de>
+           Eric Blake  <eblake@redhat.com>
+
+       docs: advise against HP-UX make due to time stamp semantics.
+       * doc/autoconf.texi (Timestamps and Make): Document HP-UX 11.31
+       make issue with targets having the same time stamps as their
+       prerequisites.
+       * doc/install.texi (Particular Systems): Warn against using
+       HP-UX make.
+
 2011-01-25  Eric Blake  <eblake@redhat.com>
 
        maint: reflect recent copyright assignments

diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index ae601a07dc0bf8fa372684e15decab71e6799606..61eb6f0621071b860e2d6eb983954448a0010350 100644 (file)
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -20287,6 +20287,14 @@ dest-stamp: src
         date >dest-stamp
 @end example
 
+Apart from timestamp resolution, there are also differences in handling
+equal timestamps.  HP-UX @command{make} updates targets if it has the
+same time stamp as one of its prerequisites, in violation of Posix rules.
+
+This can cause spurious rebuilds for repeated runs of @command{make}.
+This in turn can cause @command{make} to fail if it tries to rebuild
+generated files in a possibly read-only source tree with tools not
+present on the end-user machine.  Use GNU @command{make} instead.
 
 
 

diff --git a/doc/install.texi b/doc/install.texi
index c43298b01c906a86028ea055596cb9d4332d412d..d397b8a89b4cb3f385c702d69a8dde7072533762 100644 (file)
--- a/doc/install.texi
+++ b/doc/install.texi
@@ -261,6 +261,11 @@ use an ANSI C compiler:
 @noindent
 and if that doesn't work, install pre-built binaries of GCC for HP-UX.
 
+HP-UX @command{make} updates targets which have the same time stamps as
+their prerequisites, which makes it generally unusable when shipped
+generated files such as @command{configure} are involved.  Use GNU
+@command{make} instead.
+
 On OSF/1 a.k.a.@: Tru64, some versions of the default C compiler cannot
 parse its @code{<wchar.h>} header file.  The option @option{-nodtk} can be
 used as a workaround.  If GNU CC is not installed, it is therefore