Unix in a Nutshell, 4th Edition

Special Target Names

.DEFAULT:	Commands associated with this target are executed if make can’t find any makefile entries or suffix rules with which to build a requested target.
.DELETE_ON_ERROR:	If this target appears in a makefile, then for any target that make is rebuilding, if its command(s) exit with a nonzero status, make deletes the target.
.EXPORT_ALL_VARIABLES:	The mere existence of this target causes make to export all variables to child processes.
.IGNORE:	With prerequisites, ignore problems just for those files. For historical compatibility, with no prerequisites, ignore error returns from all commands. This is the same as the -i option.
.INTERMEDIATE:	Prerequisites for this target are treated as intermediate files, even if they are mentioned explicitly in other rules. (An intermediate file is one that needs to be built “along the way” to the real target. For example, making a .c file from a .y file, in order to create a .o object file. The .c file is an intermediate file.) This prevents them from being re-created, unless one of their prerequisites is out of date.
.LOW_RESOLUTION_TIME:	make notes that prerequisites for this target are updated by commands that only create low resolution timestamps (one second granularity). For such targets, if their modification time starts at the same second as the modification time of a prerequisite, make does not try to compare the sub-second time values, and does not treat the file as being out of date.