make: Use (almost) POSIX make for portability

[concatime]

This is portable, except for the yet-to-be standard !=.
This makefile works with BSD make (bmake) and GNU make (gmake).

# export CFLAGS=... LDFLAGS=...
make -e
sudo make PREFIX=/usr install

WDYT?

[ifreund]

Hmm, what exactly about the current Makefile isn't POSIX compliant? It already seems to work fine with bmake for me...

What error are you currently getting that this PR fixes and what make implementation are you using?

[concatime]

Well, the real motivation for this was to support pkg-config for pam (because welcome to 2010). While doing so, I decided to go (almost) full POSIX.

[ifreund]

@concatime again, what concrete problem does this fix? I'm happy to help make this project easier for distros to package but I don't want to maintain a Makefile that's any more complex than necessary.

What is the minimal patch that fixes the concrete issue you are having?

[concatime]

Sorry for the delay. When building dumb_runtime_dir, I need to specity both C_INCLUDE_PATH and LIBRARY_PATH to make. This way the compiler can find libpam. The natural solution would be to simply rely on pkg-config, and fallback to -lpam.

[ifreund]

@concatime I'm fine with using pkg-config, but there's no need to make things so complicated. Does this fix your use-case? If so I'll push it to master.

diff --git a/Makefile b/Makefile
index 82a9776..d932d10 100644
--- a/Makefile
+++ b/Makefile
@@ -1,11 +1,12 @@
 PREFIX ?= /usr
 CC ?= cc
 CFLAGS ?= -Os -Wall -Wextra -Wpedantic -Wconversion -Werror
+PAMFLAGS = $$(pkg-config --cflags --libs pam)
 
 RUNTIME_DIR_PARENT ?= "\"/run/user\""
 
-pam_dumb_runtime_dir.so:
-       $(CC) -o $@ pam_dumb_runtime_dir.c -lpam -shared -fPIC -std=c99 $(CFLAGS) \
+pam_dumb_runtime_dir.so: pam_dumb_runtime_dir.c
+       $(CC) -o $@ pam_dumb_runtime_dir.c $(PAMFLAGS) -shared -fPIC -std=c99 $(CFLAGS) \
                -DRUNTIME_DIR_PARENT=$(RUNTIME_DIR_PARENT)
 
 .PHONY: all install uninstall clean

[concatime]

Normally it should do it. Ty.

[ifreund]

@concatime Just released 1.0.2 which now uses pkg-config :)