halcompile: support HALCOMPILE_MAX_NAMES

as an environmental variable.

Users request increased quantity of names= items when
using many components with twopass processing.

Example usage:
  $ HALCOMPILE_MAX_NAMES=20 halcompile ...

Note: current default names= limit is set in halcompile.g as
      MAX_NAMES_DEFAULT = 16

docs/man/man1/halcompile.1

@@ -41,6 +41,14 @@ halcompile \- Build, compile and install LinuxCNC HAL components
 \fIsudo\fR \fBhalcompile\fR \fB\-\-install\fR \fB\-\-userspace\fR cfile...
 .PP
 \fIsudo\fR \fBhalcompile\fR \fB\-\-install\fR \fB\-\-userspace\fR pyfile...
+
+.PP
+By default, the maximum number of names= items is 16.
+To alter this limit, set the environmental variable \fBHALCOMPILE_MAX_NAMES\fR.
+Example:
+   [sudo] \fBHALCOMPILE_MAX_NAMES\fR=20 \fBhalcompile\fR ...
+
+
 .PD
 .SH DESCRIPTION
 \fBhalcompile\fR performs many different functions:

docs/src/hal/comp.txt

@@ -93,6 +93,14 @@ many numbered instances are created.  If 'count' is not specified, the
 If neither 'count' nor 'names' is specified, a single numbered instance
 is created.
 
+[NOTE}
+
+By default, the maximum number of 'names' items is 16.  To alter this
+limit, set the environmental variable HALCOMPILE_MAX_NAMES to a positive
+integer value.
+Example:
+  [sudo] HALCOMPILE_MAX_NAMES=20 halcompile ...
+
 == Implicit Parameters
 
 Functions are implicitly passed the 'period' parameter which is the time in
@@ -492,9 +500,15 @@ in a single step, placing 'rtexample.ko' in the LinuxCNC realtime
 module directory:
 
 ----
-halcompile --install rtexample.comp
+[sudo] halcompile --install rtexample.comp
 ----
 
+[NOTE]
+
+sudo (for root permission) is needed when using LinuxCNC from
+a deb package install.  When using a Run-In-Place (RIP) build,
+root privileges should not be needed.
+
 Or, it can process and compile in one step, leaving 'example.ko' (or
 'example.so' for the simulator) in the current directory:
 
@@ -512,7 +526,7 @@ halcompile rtexample.comp
 the '--install' and '--compile' options shown above:
 
 ----
-halcompile --install rtexample2.c
+[sudo] halcompile --install rtexample2.c
 ----
 
 man-format documentation can also be created from the information in
@@ -537,7 +551,7 @@ or copied to a standard location for manual pages.
 ----
 halcompile usrexample.comp
 halcompile --compile usrexample.comp
-halcompile --install usrexample.comp
+[sudo] halcompile --install usrexample.comp
 halcompile --document usrexample.comp
 ----
 

src/hal/utils/halcompile.g

@@ -21,7 +21,17 @@ import os, sys, tempfile, shutil, getopt, time
 BASE = os.path.abspath(os.path.join(os.path.dirname(sys.argv[0]), ".."))
 sys.path.insert(0, os.path.join(BASE, "lib", "python"))
 
-MAX_NAMES = 16
+MAX_NAMES_DEFAULT = 16
+try:
+    MAX_NAMES = int(os.environ['HALCOMPILE_MAX_NAMES'])
+    print("halcompile: HALCOMPILE_MAX_NAMES=",MAX_NAMES)
+except ValueError, detail:
+    print("halcompile: HALCOMPILE_MAX_NAMES\n  ",detail)
+    MAX_NAMES = MAX_NAMES_DEFAULT
+    print("   Using MAX_NAMES=",MAX_NAMES)
+except KeyError, detail:
+    MAX_NAMES = MAX_NAMES_DEFAULT
+
 MAX_PERSONALITIES = MAX_NAMES
 
 %%
@@ -1028,7 +1038,12 @@ Usage:
     [sudo] %(name)s --install --userspace cfile...
     [sudo] %(name)s --install --userspace pyfile...
            %(name)s --print-modinc
-""" % {'name': os.path.basename(sys.argv[0])})
+
+    By default, the maximum number of names= items is %(dflt)d.
+    To alter this limit, set the environmental variable HALCOMPILE_MAX_NAMES.
+    Example:
+        [sudo] HALCOMPILE_MAX_NAMES=20 %(name)s ...
+""" % {'name': os.path.basename(sys.argv[0]),'dflt': MAX_NAMES_DEFAULT})
     raise SystemExit(exitval)
 
 def main():