Document the enhancements for DEPEND and INCLUDE and use a better example

Reviewed-by: NEmilia Käsper <emilia@openssl.org>

Configurations/README

@@ -379,6 +379,18 @@ item muct be the generator file.  It is, however, entirely up to the
 build file template to define exactly how those command lines should
 be handled, how the output is captured and so on.
 
+Sometimes, the generator file itself depends on other files, for
+example if it is a perl script that depends on other perl modules.
+This can be expressed using DEPEND like this:
+
+    DEPEND[asm/something.pl]=../perlasm/Foo.pm
+
+There may also be cases where the exact file isn't easily specified,
+but an inclusion directory still needs to be specified.  INCLUDE can
+be used in that case:
+
+    INCLUDE[asm/something.pl]=../perlasm
+
 NOTE: GENERATE lines are limited to one command only per GENERATE.
 
 As a last resort, it's possible to have raw build file lines, between
@@ -498,6 +510,8 @@ They are all expected to return a string with the lines they produce.
 
                         generatesrc(src => "PATH/TO/tobegenerated",
                                     generator => [ "generatingfile", ... ]
+                                    generator_incs => [ "INCL/PATH", ... ]
+                                    generator_deps => [ "dep1", ... ]
                                     generator => [ "generatingfile", ... ]
                                     incs => [ "INCL/PATH", ... ],
                                     deps => [ "dep1", ... ],
@@ -509,11 +523,14 @@ They are all expected to return a string with the lines they produce.
                   expected to be the file to generate from.
                   generatesrc() is expected to analyse and figure out
                   exactly how to apply that file and how to capture
-                  the result.  'incs' and 'deps' are include
-                  directories and files that are used if $(CC) used as
-                  an intermediary step when generating the end product
-                  (the file indicated by 'src').  'intent' indicates
-                  what the generated file is going to be used for.
+                  the result.  'generator_incs' and 'generator_deps'
+                  are include directories and files that the generator
+                  file itself depends on.  'incs' and 'deps' are
+                  include directories and files that are used if $(CC)
+                  is used as an intermediary step when generating the
+                  end product (the file indicated by 'src').  'intent'
+                  indicates what the generated file is going to be
+                  used for.
 
     src2obj     - function that produces build file lines to build an
                   object file from source files and associated data.

Configurations/README.design

@@ -91,6 +91,7 @@ depends on the library 'libssl' to function properly.
     
     GENERATE[buildinf.h]=../util/mkbuildinf.pl "$(CC) $(CFLAGS)" "$(PLATFORM)"
     DEPEND[buildinf.h]=../Makefile
+    DEPEND[../util/mkbuildinf.pl]=../util/Foo.pm
 
 This is the build.info file in 'crypto', and it tells us a little more
 about what's needed to produce 'libcrypto'.  LIBS is used again to
@@ -104,7 +105,8 @@ source files, 'crypto/aes.c', 'crypto/evp.c' and 'crypto/cversion.c'.
 It also shows us that building the object file inferred from
 'crypto/cversion.c' depends on 'crypto/buildinf.h'.  Finally, it 
 also shows the possibility to declare how some files are generated
-using some script, in this case a perl script.
+using some script, in this case a perl script, and how such scripts
+can be declared to depend on other files, in this case a perl module.
 
 Two things are worth an extra note:
 
@@ -159,6 +161,7 @@ information comes down to this:
     
     GENERATE[crypto/buildinf.h]=util/mkbuildinf.pl "$(CC) $(CFLAGS)" "$(PLATFORM)"
     DEPEND[crypto/buildinf.h]=Makefile
+    DEPEND[util/mkbuildinf.pl]=util/Foo.pm
 
 
 A few notes worth mentioning:
@@ -169,13 +172,14 @@ PROGRAMS may be used to declare programs only.
 
 ENGINES may be used to declare engines only.
 
-The indexes for SOURCE, INCLUDE and ORDINALS must only be end product
-files, such as libraries, programs or engines.  The values of SOURCE
+The indexes for SOURCE and ORDINALS must only be end product files,
+such as libraries, programs or engines.  The values of SOURCE
 variables must only be source files (possibly generated)
 
-DEPEND shows a relationship between different produced files, such
-as a program depending on a library, or between an object file and
-some extra source file.
+INCLUDE and DEPEND shows a relationship between different files
+(usually produced files) or between files and directories, such as a
+program depending on a library, or between an object file and some
+extra source file.
 
 When Configure processes the build.info files, it will take it as
 truth without question, and will therefore perform very few checks.
@@ -266,6 +270,10 @@ section above would be digested into a %unified_info table:
                     [
                         "libcrypto",
                     ],
+                "util/mkbuildinf.pl" =>
+                    [
+                        "util/Foo.pm",
+                    ],
             },
         "engines" =>
             [
@@ -300,6 +308,10 @@ section above would be digested into a %unified_info table:
                     [
                         "include",
                     ],
+                "util/mkbuildinf.pl" =>
+                    [
+                        "util",
+                    ],
             }
         "libraries" =>
             [
@@ -403,6 +415,8 @@ etc.
 
                         generatesrc(src => "PATH/TO/tobegenerated",
                                     generator => [ "generatingfile", ... ]
+                                    generator_incs => [ "INCL/PATH", ... ]
+                                    generator_deps => [ "dep1", ... ]
                                     incs => [ "INCL/PATH", ... ],
                                     deps => [ "dep1", ... ],
                                     intent => one of "libs", "dso", "bin" );
@@ -413,11 +427,14 @@ etc.
                   expected to be the file to generate from.
                   generatesrc() is expected to analyse and figure out
                   exactly how to apply that file and how to capture
-                  the result.  'incs' and 'deps' are include
-                  directories and files that are used if $(CC) used as
-                  an intermediary step when generating the end product
-                  (the file indicated by 'src').  'intent' indicates
-                  what the generated file is going to be used for.
+                  the result.  'generator_incs' and 'generator_deps'
+                  are include directories and files that the generator
+                  file itself depends on.  'incs' and 'deps' are
+                  include directories and files that are used if $(CC)
+                  is used as an intermediary step when generating the
+                  end product (the file indicated by 'src').  'intent'
+                  indicates what the generated file is going to be
+                  used for.
 
     src2obj     - function that produces build file lines to build an
                   object file from source files and associated data.
@@ -538,7 +555,7 @@ programs and all intermediate files, using the rule generating
 functions defined in the build-file template.
 
 As an example with the smaller build.info set we've seen as an
-example, producing the rules to build 'libssl' would result in the
+example, producing the rules to build 'libcrypto' would result in the
 following calls:
 
     # Note: libobj2shlib will only be called if shared libraries are
@@ -548,20 +565,41 @@ following calls:
     # to the implementation to decide which to use as input.
     # Note 3: common.tmpl peals off the ".o" extension from all object
     # files, as the platform at hand may have a different one.
-    libobj2shlib(shlib => "libssl",
-                 lib => "libssl",
-                 objs => [ "ssl/tls" ],
-                 deps => [ "libcrypto" ]
-                 ordinals => [ "ssl", "util/libssl.num" ]);
+    libobj2shlib(shlib => "libcrypto",
+                 lib => "libcrypto",
+                 objs => [ "crypto/aes", "crypto/evp", "crypto/cversion" ],
+                 deps => [  ]
+                 ordinals => [ "crypto", "util/libcrypto.num" ]);
+
+    obj2lib(lib => "libcrypto"
+            objs => [ "crypto/aes", "crypto/evp", "crypto/cversion" ]);
 
-    obj2lib(lib => "libssl"
-            objs => [ "ssl/tls" ]);
+    src2obj(obj => "crypto/aes"
+            srcs => [ "crypto/aes.c" ],
+            deps => [ ],
+            incs => [ "include" ],
+            intent => "lib");
 
-    src2obj(obj => "ssl/tls"
-            srcs => [ "ssl/tls.c" ],
+    src2obj(obj => "crypto/evp"
+            srcs => [ "crypto/evp.c" ],
             deps => [ ],
             incs => [ "include" ],
             intent => "lib");
 
+    src2obj(obj => "crypto/cversion"
+            srcs => [ "crypto/cversion.c" ],
+            deps => [ "crypto/buildinf.h" ],
+            incs => [ "include" ],
+            intent => "lib");
+
+    generatesrc(src => "crypto/buildinf.h",
+                generator => [ "util/mkbuildinf.pl", "\"$(CC)",
+                               "$(CFLAGS)\"", "\"$(PLATFORM)\"" ],
+                generator_incs => [ "util" ],
+                generator_deps => [ "util/Foo.pm" ],
+                incs => [ ],
+                deps => [ ],
+                intent => "lib");
+
 The returned strings from all those calls are then concatenated
 together and written to the resulting build-file.