-------------------------------------------------------------------------------
Shell scripts in Makefile
  You must backslash all lines to make them a single line, also
hiding the resultact command is usful.
    FILE_TEST:
            @echo "performing sheel commands"
            @if [ -f file ]; \
            then set -x; \
                    command args... \
            fi
OR
    .ENV_CHECK:
            @if [ $(PMISSOURCE) != "/p7" ]; then exit 1; fi
OR
    .ENV_CHECK:
            @[ $(PMISSOURCE) != "/p7" && exit 1

-------------------------------------------------------------------------------
Make options

   -k      Continue other dependancies after an error (don't stop)
   -t      touch all so that everything is actually ok

-------------------------------------------------------------------------------
Full ANSI/OSI error checking with gcc

CC     = gcc
CFLAGS = -Wall -Wpointer-arith -Wconversion       \
         -Wstrict-prototypes -Wmissing-prototypes \
         -ansi -pedantic -g -O                    \
         #-DDEBUG 

-------------------------------------------------------------------------------
Selective recompile after a header edit

     make -t
     touch  module_to_recompile
     make

-------------------------------------------------------------------------------
Adding a new make rule
Convert .c into a .cgi program

    .c.cgi:
	    $(CC) $(CFLAGS) -o $@ $< $(LIBS)
	    chmod 755 $@

    .SUFFIXES:
    .SUFFIXES: .cgi $(SUFFIXES)

-------------------------------------------------------------------------------
Substitutions Rules

# Sed substitions rule
.sed: 
        @echo "SED SUBSTITUTIONS \"$@.sed\" ==> \"$@\""
        @sed -e 's|==BROWSERDIR==|$(BROWSERDIR)|' \
             -e 's|==LIBRARY_RC==|$(LIBRARY_RC)|' \
             -e 's|==USERS_RC==|$(USERS_RC)|'     \
             -e 's|==X_BITMAPS==|$(X_BITMAPS)|'   \
             -e '/==COLOR_SETTINGS_DIVIDER==/d'   \
             < $@.sed  >$@
.SUFFIXES: .sed

Some of the special character around the substition strings are
as follows so take your pick.

  ==LABEL==    @@LABEL@@    @#LABEL#@


-------------------------------------------------------------------------------
Hiding intermediate object files (for large programs)

  Subdirectories :  bin upstairs, objects in sub-directory

  BIN = ../bin/
  OBJ = obj/

  TARGET = $(BIN)foo
  OBJS =  $(OBJ)ack.o \
	  $(OBJ)bar.o \
	  $(OBJ)frotz.o \
	  $(OBJ)ozmoo.o

  $(TARGET): $(OBJS)
	  @echo "Linking $@"
	  @$(LINK.c) -o $@ $?

  $(OBJ)%.o: %.c
	  @echo "Compiling $<"
	  @$(COMPILE.c) -o $@ $<

  Of course, this is oversimplified.  However, it should give you the idea.
  The LINK.c and COMPILE.c are predefined macros supplied with the version
  of make that comes with SunOS, and all they are is predefined 'cc' commands. 
  'man make' for more info about predefined macros on your system.

  The above example ensures that your source, executable, and objects are
  separate.  Of course, depending on how large the project is, you could
  make an inc/ directory also to separate your include files.  Of course
  you would have to define that dir in your makefile as well.

-------------------------------------------------------------------------------
Auto-increment of a build version number

  Makefile.autoincr.gen : Integers only!
    VERSION = 23
    NEWVERS = `expr $(VERSION) + $(UDVAL)`
 
    update:
            @mv Makefile Makefile.bak
            @sed "s/^VERSION[ \t]*=[ \t]*[0-9]*/VERSION = $(NEWVERS)/" \
               Makefile.bak > Makefile

  Makefile.autoincr.sun : Bells & whistles!
    VERSION = 1.23
    NEWVERS = echo "scale=2 ; $(VERSION) + $(UDVAL)" | bc

    update:
            @mv Makefile Makefile.bak
            @sed "s/^VERSION[ \t]*=[ \t]*[0-9.]*/VERSION = $(NEWVERS:sh)/" \
               Makefile.bak > Makefile

  Then the following can be used to update the version number
  
       make   -f Makefile.autoincr.sun   update   UDVAL="0.01"


Another way is to have the version in a separate file and increment this.
   
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