Step 1 of the switch to support configuration with NPTL:

Rename 'IS_LINUX' configuration variable to 'TARGET_LINUX'.

scripts/Makefile.am

@@ -135,7 +135,7 @@ SUFFIXES = .sh
 	  -e 's!@''MYSQLD_DEFAULT_SWITCHES''@!@MYSQLD_DEFAULT_SWITCHES@!' \
 	  -e 's!@''MYSQL_UNIX_ADDR''@!@MYSQL_UNIX_ADDR@!' \
 	  -e 's!@''MYSQL_TCP_PORT''@!@MYSQL_TCP_PORT@!' \
-	  -e 's!@''IS_LINUX''@!@IS_LINUX@!' \
+	  -e 's!@''TARGET_LINUX''@!@TARGET_LINUX@!' \
 	  -e "s!@""CONF_COMMAND""@!@CONF_COMMAND@!" \
 	  -e 's!@''MYSQLD_USER''@!@MYSQLD_USER@!' \
 	  -e 's!@''STATIC_NSS_FLAGS''@!@STATIC_NSS_FLAGS@!' \

scripts/mysqld_safe.sh

@@ -324,7 +324,7 @@ do
     break
   fi
 
-  if @IS_LINUX@ && test $KILL_MYSQLD -eq 1
+  if @TARGET_LINUX@ && test $KILL_MYSQLD -eq 1
   then
     # Test if one process was hanging.
     # This is only a fix for Linux (running as base 3 mysqld processes)