Add comments to Makefile explaining env vars

[atomicules (via pkgsrc-wip) <commit-notify%pkgsrc.org@localhost>]

Module Name:	pkgsrc-wip
Committed By:	atomicules <base%atomicules.co.uk@localhost>
Pushed By:	atomicules
Date:		Wed Nov 12 19:59:08 2025 +0000
Changeset:	6d96d953ce4bf55fd0d2caba28fda8835047872c

Modified Files:
	helix/Makefile

Log Message:
Add comments to Makefile explaining env vars

Since the previous git commit message will be lost to the ether

To see a diff of this commit:
https://wip.pkgsrc.org/cgi-bin/gitweb.cgi?p=pkgsrc-wip.git;a=commitdiff;h=6d96d953ce4bf55fd0d2caba28fda8835047872c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

diffstat:
 helix/Makefile | 2 ++
 1 file changed, 2 insertions(+)

diffs:
diff --git a/helix/Makefile b/helix/Makefile
index 32d0481788..61dabf3e43 100644
--- a/helix/Makefile
+++ b/helix/Makefile
@@ -16,6 +16,7 @@ WRKSRC=		${WRKDIR}/${DISTNAME:S/-source//}
 USE_LANGUAGES=	c c++
 USE_TOOLS+=	git pax
 MAKE_ENV+=	HELIX_DISABLE_AUTO_GRAMMAR_BUILD=1
+# Set per: https://docs.helix-editor.com/building-from-source.html#note-to-packagers
 MAKE_ENV+=	HELIX_DEFAULT_RUNTIME=${PREFIX}/share/helix/runtime
 
 INSTALLATION_DIRS+=	bin
@@ -34,6 +35,7 @@ post-extract:
 
 .include "../../mk/bsd.prefs.mk"
 
+# Cargo manifest since highest precedence: https://docs.helix-editor.com/building-from-source.html#multiple-runtime-directories
 post-build:
 	${RUN} cd ${WRKSRC} && ${SETENV} CARGO_MANIFEST_DIR=${WRKSRC}/runtime \
 		./target/release/hx --grammar build