Makefile: allow setting KEEP_SYMBOLS=1

The symbols are needed for applying gomodjail (library sandbox) to Lima.
https://github.com/AkihiroSuda/gomodjail

This grows the `limactl` binary from 27M to 30M.

Ideally, Makefile should rather separate the `install-split` target from the
`install` target as in GNU's C programs.
However, this is not possible with the current version of Go, as there is no
`go tool strip` command.

Signed-off-by: Akihiro Suda <[email protected]>

Author: AkihiroSuda

Diff for: Makefile

@@ -46,7 +46,12 @@ PACKAGE := github.com/lima-vm/lima
 VERSION := $(shell git describe --match 'v[0-9]*' --dirty='.m' --always --tags)
 VERSION_TRIMMED := $(VERSION:v%=%)
 
-GO_BUILD_LDFLAGS := -ldflags="-s -w -X $(PACKAGE)/pkg/version.Version=$(VERSION)"
+KEEP_SYMBOLS ?=
+GO_BUILD_LDFLAGS_S := true
+ifeq ($(KEEP_SYMBOLS),1)
+	GO_BUILD_LDFLAGS_S = false
+endif
+GO_BUILD_LDFLAGS := -ldflags="-s=$(GO_BUILD_LDFLAGS_S) -w -X $(PACKAGE)/pkg/version.Version=$(VERSION)"
 # `go -version -m` returns -tags with comma-separated list, because space-separated list is deprecated in go1.13.
 # converting to comma-separated list is useful for comparing with the output of `go version -m`.
 GO_BUILD_FLAG_TAGS := $(addprefix -tags=,$(shell echo "$(GO_BUILDTAGS)"|tr " " "\n"|paste -sd "," -))
@@ -68,7 +73,15 @@ help:
 	@echo  '  binaries        - Build all binaries'
 	@echo  '  manpages        - Build manual pages'
 	@echo
-	@echo  "  Use 'make help-targets' to see additional targets."
+	@echo  '  help-variables  - Show Makefile variables'
+	@echo  '  help-targets    - Show additional Makefile targets'
+
+.PHONY: help-varaibles
+help-variables:
+	@echo  '# Variables that can be overridden.'
+	@echo
+	@echo  '- PREFIX       (directory)  : Installation prefix (default: /usr/local)'
+	@echo  '- KEEP_SYMBOLS (1 or 0)     : Whether to keep symbols (default: 0)'
 
 .PHONY: help-targets
 help-targets:

Diff for: website/content/en/docs/installation/_index.md

@@ -60,6 +60,8 @@ make install
 
 The installation directory (`$PREFIX`) defaults to `/usr/local`.
 
+Run `make help-variables` to show other Makefile variables.
+
 #### Advanced configuration with Kconfig tools
 (This step is not needed for most users)