Do not include gnatcoll-projects related package for cross environments

Gnatcoll "projects" features are not required by all use cases, like for
the cross environment, and adds dependency towards GPR.

This commit moves these features in a sub directory, which is added as a
source directory when GNATCOLL_PROJECTS environment variable is set to
"yes" (which is the default value).

Issue: gnatcoll-core#12

Change-Id: Id27813df9f477766717553c0a91be834b250dabf

Author: Jicquel

Makefile

@@ -43,15 +43,18 @@
 #
 # Project specific:
 #
-#   GNATCOLL_MMAP    : whether MMAP is supported (yes/no)
-#                      default is "yes"; has no effect on Windows
-#   GNATCOLL_MADVISE : whether MADVISE is supported (yes/no)
-#                      default is "yes"; has no effect on Windows
+#   GNATCOLL_MMAP     : whether MMAP is supported (yes/no)
+#                       default is "yes"; has no effect on Windows
+#   GNATCOLL_MADVISE  : whether MADVISE is supported (yes/no)
+#                       default is "yes"; has no effect on Windows
+#   GNATCOLL_PROJECTS : whether GNATCOLL projects package is included (yes/no)
+#                       default is "yes";
 
 # helper programs
 CAT := cat
 ECHO  := echo
 WHICH := which
+SED := sed
 
 # check for out-of-tree build
 SOURCE_DIR := $(dir $(MAKEFILE_LIST))
@@ -83,6 +86,7 @@ prefix := $(dir $(shell $(WHICH) gnatls))..
 GNATCOLL_VERSION := $(shell $(CAT) $(SOURCE_DIR)/version_information)
 GNATCOLL_MMAP := yes
 GNATCOLL_MADVISE := yes
+GNATCOLL_PROJECTS := yes
 
 BUILD         = PROD
 PROCESSORS    = 0
@@ -123,6 +127,7 @@ endif
 
 GPR_VARS=-XGNATCOLL_MMAP=$(GNATCOLL_MMAP) \
 	 -XGNATCOLL_MADVISE=$(GNATCOLL_MADVISE) \
+	 -XGNATCOLL_PROJECTS=$(GNATCOLL_PROJECTS) \
 	 -XGNATCOLL_VERSION=$(GNATCOLL_VERSION) \
 	 -XGNATCOLL_OS=$(GNATCOLL_OS) \
 	 -XBUILD=$(BUILD)
@@ -145,6 +150,18 @@ UNINSTALLER=$(INSTALLER) -p -f --install-name=gnatcoll --uninstall
 build: $(LIBRARY_TYPES:%=build-%)
 
 build-%: $(GNATCOV_RTS)
+
+# Gnatcoll projects related packages need libgpr. As conditional
+# with does not exist in GPR, `with "gpr"` at the beginning of
+# gnatcoll.gpr needs to be commented or uncommented depending on
+# the user choice.
+
+ifeq ($(GNATCOLL_PROJECTS), yes)
+	$(SED) -i 's/^--  with "gpr"/with "gpr"/g' $(GNATCOLL_GPR)
+else
+	$(SED) -i 's/^with "gpr"/--  with "gpr"/g' $(GNATCOLL_GPR)
+endif
+
 ifeq ($(GNATCOV), yes)
 	$(GNATCOV_PROJECT_PATH) gnatcov instrument -P $(GNATCOLL_GPR) $(RBD) \
 		--no-subprojects --level=stmt+decision
@@ -204,6 +221,7 @@ setup:
 	$(ECHO) "GNATCOLL_VERSION=$(GNATCOLL_VERSION)" >> makefile.setup
 	$(ECHO) "GNATCOLL_MMAP=$(GNATCOLL_MMAP)" >> makefile.setup
 	$(ECHO) "GNATCOLL_MADVISE=$(GNATCOLL_MADVISE)" >> makefile.setup
+	$(ECHO) "GNATCOLL_PROJECTS=$(GNATCOLL_PROJECTS)" >> makefile.setup
 
 # Let gprbuild handle parallelisation. In general, we don't support parallel
 # runs in this Makefile, as concurrent gprinstall processes may crash.

gnatcoll.gpr

@@ -29,8 +29,9 @@ project GnatColl is
    Name    := "gnatcoll";
 
    type Yes_No is ("yes", "no");
-   Mmap      : Yes_No := External ("GNATCOLL_MMAP", "yes");
-   Madvise   : Yes_No := External ("GNATCOLL_MADVISE", "yes");
+   Mmap     : Yes_No := External ("GNATCOLL_MMAP", "yes");
+   Madvise  : Yes_No := External ("GNATCOLL_MADVISE", "yes");
+   Projects : Yes_No := External ("GNATCOLL_PROJECTS", "yes");
 
    type Build_Type is ("DEBUG", "PROD");
    Build : Build_Type :=
@@ -51,6 +52,13 @@ project GnatColl is
          Sources := Sources & ("src/os/win32");
    end case;
 
+   case Projects is
+      when "yes" =>
+         Sources := Sources & ("src/projects");
+      when others =>
+         null;
+   end case;
+
    for Source_Dirs use Sources;
 
    for Library_Kind use Library_Type;