C API: move to src/lib*/c/

src/libexpr/c/local.mk

@@ -0,0 +1,19 @@
+libraries += libexprc
+
+libexprc_NAME = libnixexprc
+
+libexprc_DIR := $(d)
+
+libexprc_SOURCES := \
+  $(wildcard $(d)/*.cc) \
+
+libexprc_CXXFLAGS += -I src/libutil -Isrc/libfetchers -I src/libstore -I src/libstorec -I src/libexpr -I src/libutil/c -I src/libstore/c
+
+libexprc_LIBS = libutil libutilc libstorec libexpr
+
+libexprc_LDFLAGS += -pthread
+
+$(eval $(call install-file-in, $(d)/nix-expr-c.pc, $(libdir)/pkgconfig, 0644))
+
+libexprc_FORCE_INSTALL := 1
+

src/libexpr/c/nix-expr-c.pc.in

@@ -0,0 +1,10 @@
+prefix=@prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: Nix
+Description: Nix Package Manager - C API
+Version: @PACKAGE_VERSION@
+Requires: nix-store-c
+Libs: -L${libdir} -lnixexprc
+Cflags: -I${includedir}/nix