Make style.json runtime path configurable via PREFIX

style.cpp's getConfigPath() searches three hardcoded paths for the
plugin's style.json. The second of these was a literal
/usr/local/etc/magnetophon/style/style.json, which downstream
packagers (Nix, distros installing to non-/usr/local prefixes)
had to rewrite via sed/substituteInPlace to point at their actual
install location.

Replace the hardcoded literal with a MAGNETOPHON_SYSCONFDIR
compile-time macro, fallback /usr/local/etc/magnetophon. The
top-level Makefile derives this from $(PREFIX)/etc/$(pkgname)
and passes it to the common sub-make as SYSCONFDIR, which adds
-DMAGNETOPHON_SYSCONFDIR="$(SYSCONFDIR)" to style.cpp's compile
line specifically. C++ adjacent string literal concatenation then
joins the path with '/style/style.json' at the call site.

Use runtime_sysconfdir = $(PREFIX)/etc rather than $(sysconfdir)
= $(DESTDIR)$(PREFIX)/etc, because the compile-time path should
reflect where the file ends up after installation, not where a
staged install temporarily writes it.

Also switch the shebangs of generate-ttl.sh and patch/apply.sh
from #!/bin/bash to #!/usr/bin/env bash. Both scripts are
POSIX-compatible anyway; env-based shebangs work uniformly across
build environments (Nix sandbox, BSD, macOS-with-Homebrew-bash)
without requiring patchShebangs.

Allows the nixpkgs derivation to drop both substituteInPlace and
patchShebangs from its postPatch hook, and switch installFlags to
makeFlags so PREFIX reaches both the build (for the macro) and
the install (for destination paths).

Author: magnetophon

plugin/dpf/Makefile

@@ -62,6 +62,11 @@ vst3dir ?= $(DESTDIR)$(PREFIX)/lib/vst3
 clapdir ?= $(DESTDIR)$(PREFIX)/lib/clap
 bindir ?= $(DESTDIR)$(PREFIX)/bin
 sysconfdir ?= $(DESTDIR)$(PREFIX)/etc
+# Where installed config files will be found at runtime, excluding any
+# DESTDIR staging prefix (which only affects where the install step
+# writes them, not where the running binary looks for them). Compile
+# time uses this; install time uses $(sysconfdir) above.
+runtime_sysconfdir ?= $(PREFIX)/etc
 datarootdir ?= $(DESTDIR)$(PREFIX)/share
 datadir ?= $(datarootdir)
 docdir ?= $(datarootdir)/doc
@@ -72,7 +77,7 @@ dpf: patch
 
 .PHONY: common
 common: dpf
-	$(MAKE) -C common
+	$(MAKE) -C common SYSCONFDIR=$(runtime_sysconfdir)/$(pkgname)
 
 .PHONY: DigiDrie
 DigiDrie: common

plugin/dpf/common/Makefile

@@ -1,11 +1,26 @@
 BUILD_DIR = ../build/common
 
+# Where style.json will live at runtime (excluding any DESTDIR staging
+# prefix). Set by the top-level Makefile from $(PREFIX)/etc/$(pkgname);
+# overridable if invoking this sub-make directly.
+SYSCONFDIR ?= /usr/local/etc/magnetophon
+
+CXXFLAGS_COMMON = -Wall -std=c++17 -O3 -fPIC
+
 OBJ := \
 	$(BUILD_DIR)/gui/style.o \
 	$(BUILD_DIR)/gui/TinosBoldItalic.o \
 
 build: $(OBJ)
 
+# style.cpp's runtime path lookup is configured at compile time via
+# MAGNETOPHON_SYSCONFDIR. The shell sees the \" sequences and turns
+# them into literal " characters, so g++ sees -DMACRO="value", which
+# in turn defines the macro as a C string literal.
+$(BUILD_DIR)/gui/style.o : gui/style.cpp
+	@mkdir -p $(dir $@)
+	g++ $(CXXFLAGS_COMMON) -DMAGNETOPHON_SYSCONFDIR=\"$(SYSCONFDIR)\" -c -o $@ $<
+
 $(BUILD_DIR)/%.o : %.cpp
 	@mkdir -p $(dir $@)
-	g++ -Wall -std=c++17 -O3 -fPIC -c -o $@ $<
+	g++ $(CXXFLAGS_COMMON) -c -o $@ $<

plugin/dpf/common/gui/style.cpp

@@ -45,6 +45,16 @@ inline fs::path getXdgConfigHome()
   return fs::path("");
 }
 
+// The local-prefix system config path is set at compile time so that
+// downstream packagers (Nix, distros installing to a non-/usr/local
+// PREFIX, etc.) can point this lookup at their actual install location
+// via -DMAGNETOPHON_SYSCONFDIR=...  The third lookup below (/etc) and
+// the first ($XDG_CONFIG_HOME) are intentionally hardcoded — those are
+// standard system / user paths that don't follow a build-time prefix.
+#ifndef MAGNETOPHON_SYSCONFDIR
+#  define MAGNETOPHON_SYSCONFDIR "/usr/local/etc/magnetophon"
+#endif
+
 inline void logNotExist(fs::path path)
 {
   std::cerr << path << " is not regular file or doesn't exist.\n";
@@ -56,7 +66,7 @@ inline fs::path getConfigPath()
   if (fs::is_regular_file(styleJsonPath)) return styleJsonPath;
   logNotExist(styleJsonPath);
 
-  styleJsonPath = fs::path("/usr/local/etc/magnetophon/style/style.json");
+  styleJsonPath = fs::path(MAGNETOPHON_SYSCONFDIR "/style/style.json");
   if (fs::is_regular_file(styleJsonPath)) return styleJsonPath;
   logNotExist(styleJsonPath);
 

plugin/dpf/generate-ttl.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -e
 

plugin/dpf/patch/apply.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 #
 # Note that this script assumes patch will be applied correctly.
 #