Search notes:

AC_CHECK_PROGS

AC_CHECK_PROGS(var, progs, val-if-not-found)
Sets $var to the first program found in the progs list or sets it to val-if-not-found otherwise. 
AC_CHECK_PROGS([TAR], [tar gtar], [na])
if test "$TAR" = na; then
   AC_MSG_ERROR([tar or gtar needed]) 
fi

See also

Autoconf compiler checks

Index

Fatal error: Uncaught PDOException: SQLSTATE[HY000]: General error: 8 attempt to write a readonly database in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php:78 Stack trace: #0 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(78): PDOStatement->execute(Array) #1 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(30): insert_webrequest_('/notes/developm...', 1759612251, '216.73.216.149', 'Mozilla/5.0 App...', NULL) #2 /home/httpd/vhosts/renenyffenegger.ch/httpsdocs/notes/development/GNU/toolchain/Build-System/Autoconf/macros/AC_CHECK_PROGS(45): insert_webrequest() #3 {main} thrown in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php on line 78