Auto: mirroring installation structure in build tree.

This makes the build tree more organized, which is good for adding new
stuff.  Now, it's useful for example for adding manual pages in man3/,
but it may be useful in the future for example for extending the build
system to run linters (e.g., clang-tidy(1), Clang analyzer, ...) on the
C source code.

Previously, the build tree was quite flat, and looked like this (after
`./configure && make`):

    $ tree -I src build
    build
    ├── Makefile
    ├── autoconf.data
    ├── autoconf.err
    ├── echo
    ├── libnxt.a
    ├── nxt_auto_config.h
    ├── nxt_version.h
    ├── unitd
    └── unitd.8

    1 directory, 9 files

And after this patch, it looks like this:

    $ tree -I src build
    build
    ├── Makefile
    ├── autoconf.data
    ├── autoconf.err
    ├── bin
    │   └── echo
    ├── include
    │   ├── nxt_auto_config.h
    │   └── nxt_version.h
    ├── lib
    │   ├── libnxt.a
    │   └── unit
    │       └── modules
    ├── sbin
    │   └── unitd
    ├── share
    │   └── man
    │       └── man8
    │           └── unitd.8
    └── var
        ├── lib
        │   └── unit
        ├── log
        │   └── unit
        └── run
            └── unit

    17 directories, 9 files

It also solves one issue introduced in
5a37171f733f ("Added default values for pathnames.").  Before that
commit, it was possible to run unitd from the build system
(`./build/unitd`).  Now, since it expects files in a very specific
location, that has been broken.  By having a directory structure that
mirrors the installation, it's possible to trick it to believe it's
installed, and run it from there:

    $ ./configure --prefix=./build
    $ make
    $ ./build/sbin/unitd

Fixes: 5a37171f733f ("Added default values for pathnames.")
Reported-by: Liam Crilly <liam@nginx.com>
Reviewed-by: Konstantin Pavlov <thresh@nginx.com>
Reviewed-by: Andrew Clayton <a.clayton@nginx.com>
Cc: Andrei Zeliankou <zelenkov@nginx.com>
Cc: Zhidao Hong <z.hong@f5.com>
Signed-off-by: Alejandro Colomar <alx@nginx.com>

7 files changed, 32 insertions, 34 deletions

diff --git a/auto/modules/go b/auto/modules/go
index a8596bf3..86dfb62d 100644
--- a/auto/modules/go
+++ b/auto/modules/go
@@ -119,15 +119,15 @@ ${NXT_GO}-install-src:
 	install -p -m644 ./go/* \$(DESTDIR)\$(NXT_GO_DST)/src/${NXT_GO_PKG}/
 
 ${NXT_GO}-install-env: \$(DESTDIR)\$(NXT_GO_DST)/src/${NXT_GO_PKG}/env.go \
-    ${NXT_VERSION_H} ${NXT_BUILD_DIR}/${NXT_LIB_UNIT_STATIC}
+    ${NXT_VERSION_H} ${NXT_BUILD_DIR}/lib/${NXT_LIB_UNIT_STATIC}
 
 \$(DESTDIR)\$(NXT_GO_DST)/src/${NXT_GO_PKG}/env.go:
 	install -d \$(DESTDIR)\$(NXT_GO_DST)/src/${NXT_GO_PKG}
 	$echo "package unit" > \$@
 	$echo "/*" >> \$@
 	$echo "#cgo CFLAGS: ${CFLAGS} ${NXT_CC_OPT}" >> \$@
-	$echo "#cgo CPPFLAGS: -I${PWD}/src -I${PWD}/${NXT_BUILD_DIR}" >> \$@
-	$echo "#cgo LDFLAGS: -L${PWD}/${NXT_BUILD_DIR} ${NXT_GO_LDFLAGS} ${NXT_LD_OPT}" >> \$@
+	$echo "#cgo CPPFLAGS: -I${PWD}/src -I${PWD}/${NXT_BUILD_DIR}/include" >> \$@
+	$echo "#cgo LDFLAGS: -L${PWD}/${NXT_BUILD_DIR}/lib ${NXT_GO_LDFLAGS} ${NXT_LD_OPT}" >> \$@
 	$echo "*/" >> \$@
 	$echo 'import "C"' >> \$@
 
diff --git a/auto/modules/java b/auto/modules/java
index a6ce5e81..d87f93c5 100644
--- a/auto/modules/java
+++ b/auto/modules/java
@@ -320,7 +320,7 @@ fi
 
 NXT_JAVA_MOUNTS_HEADER=nxt_${NXT_JAVA_MODULE}_mounts.h
 
-cat << END > $NXT_BUILD_DIR/$NXT_JAVA_MOUNTS_HEADER
+cat << END > $NXT_BUILD_DIR/include/$NXT_JAVA_MOUNTS_HEADER
 #ifndef _NXT_JAVA_MOUNTS_H_INCLUDED_
 #define _NXT_JAVA_MOUNTS_H_INCLUDED_
 
@@ -520,23 +520,23 @@ cat << END >> $NXT_MAKEFILE
 
 all: ${NXT_JAVA_MODULE}
 
-${NXT_JAVA_MODULE}: $NXT_BUILD_DIR/${NXT_JAVA_MODULE}.unit.so \
+${NXT_JAVA_MODULE}: $NXT_BUILD_DIR/lib/unit/modules/${NXT_JAVA_MODULE}.unit.so \
     $NXT_BUILD_DIR/$NXT_UNIT_JAR \
     $NXT_BUILD_DIR/$NXT_WS_API_JAR
 
-$NXT_BUILD_DIR/${NXT_JAVA_MODULE}.unit.so: $nxt_objs
-	\$(NXT_MODULE_LINK) -o $NXT_BUILD_DIR/${NXT_JAVA_MODULE}.unit.so \\
-	$nxt_objs $NXT_JAVA_LDFLAGS $NXT_LD_OPT
+$NXT_BUILD_DIR/lib/unit/modules/${NXT_JAVA_MODULE}.unit.so: $nxt_objs
+	\$(NXT_MODULE_LINK) -o \$@ $nxt_objs $NXT_JAVA_LDFLAGS $NXT_LD_OPT
 
 
 install: ${NXT_JAVA_MODULE}-install
 
-${NXT_JAVA_MODULE}-install: $NXT_BUILD_DIR/${NXT_JAVA_MODULE}.unit.so \\
+${NXT_JAVA_MODULE}-install: \\
+    $NXT_BUILD_DIR/lib/unit/modules/${NXT_JAVA_MODULE}.unit.so \\
     $NXT_BUILD_DIR/$NXT_UNIT_JAR \\
     $NXT_BUILD_DIR/$NXT_WS_API_JAR \\
     java-shared-install
 	install -d \$(DESTDIR)$NXT_MODULESDIR
-	install -p $NXT_BUILD_DIR/${NXT_JAVA_MODULE}.unit.so \\
+	install -p $NXT_BUILD_DIR/lib/unit/modules/${NXT_JAVA_MODULE}.unit.so \\
 		\$(DESTDIR)$NXT_MODULESDIR/
 	install -d \$(DESTDIR)$NXT_JARS
 	install -p -m 0644 $NXT_BUILD_DIR/$NXT_UNIT_JAR \$(DESTDIR)$NXT_JARS/
diff --git a/auto/modules/nodejs b/auto/modules/nodejs
index 7d4f8581..968f3fdf 100644
--- a/auto/modules/nodejs
+++ b/auto/modules/nodejs
@@ -129,7 +129,7 @@ NXT_NODE_VERSION_FILE=${NXT_BUILD_DIR}/src/${NXT_NODE}/version.h
 NXT_NODE_PACKAGE_FILE=${NXT_BUILD_DIR}/src/${NXT_NODE}/package.json
 NXT_NODE_EXPORTS="export UNIT_SRC_PATH=${PWD}/src \
     && export UNIT_BUILD_PATH=${PWD}/${NXT_BUILD_DIR} \
-    && export UNIT_LIB_STATIC_PATH=${PWD}/${NXT_BUILD_DIR}/libunit.a"
+    && export UNIT_LIB_STATIC_PATH=${PWD}/${NXT_BUILD_DIR}/lib/libunit.a"
 
 if [ -n "$NXT_NODE_LOCAL" ]; then
     NXT_NODE_INSTALL=local-install
@@ -149,7 +149,7 @@ cat << END >> $NXT_MAKEFILE
 .PHONY: ${NXT_NODE}-build
 .PHONY: ${NXT_NODE}-publish
 
-${NXT_NODE}: ${NXT_NODE}-copy $NXT_BUILD_DIR/$NXT_LIB_UNIT_STATIC
+${NXT_NODE}: ${NXT_NODE}-copy $NXT_BUILD_DIR/lib/$NXT_LIB_UNIT_STATIC
 	${NXT_NODE_EXPORTS} && \\
 	cd ${NXT_NODE_TMP} && ${NXT_NODE_GYP} configure build clean
 
@@ -201,7 +201,7 @@ ${NXT_NODE}-local-check:
 	    exit 1)
 
 ${NXT_NODE}-local-install: ${NXT_NODE_TARBALL} ${NXT_NODE}-local-check \
-    $NXT_BUILD_DIR/$NXT_LIB_UNIT_STATIC
+    $NXT_BUILD_DIR/lib/$NXT_LIB_UNIT_STATIC
 	${NXT_NODE_EXPORTS} && \\
 	mkdir -p \$(DESTDIR)${NXT_NODE_LOCAL} && \\
 	cd \$(DESTDIR)${NXT_NODE_LOCAL} && \\
diff --git a/auto/modules/perl b/auto/modules/perl
index 94f06879..3c88ef0e 100644
--- a/auto/modules/perl
+++ b/auto/modules/perl
@@ -185,18 +185,17 @@ cat << END >> $NXT_MAKEFILE
 
 all: ${NXT_PERL_MODULE}
 
-${NXT_PERL_MODULE}:	$NXT_BUILD_DIR/${NXT_PERL_MODULE}.unit.so
+${NXT_PERL_MODULE}:	$NXT_BUILD_DIR/lib/unit/modules/${NXT_PERL_MODULE}.unit.so
 
-$NXT_BUILD_DIR/${NXT_PERL_MODULE}.unit.so:	$nxt_objs
-	\$(NXT_MODULE_LINK) -o $NXT_BUILD_DIR/${NXT_PERL_MODULE}.unit.so \\
-	$nxt_objs $NXT_PERL_LDOPTS $NXT_LD_OPT
+$NXT_BUILD_DIR/lib/unit/modules/${NXT_PERL_MODULE}.unit.so:	$nxt_objs
+	\$(NXT_MODULE_LINK) -o \$@ $nxt_objs $NXT_PERL_LDOPTS $NXT_LD_OPT
 
 
 install: ${NXT_PERL_MODULE}-install
 
 ${NXT_PERL_MODULE}-install: ${NXT_PERL_MODULE} install-check
 	install -d \$(DESTDIR)$NXT_MODULESDIR
-	install -p $NXT_BUILD_DIR/${NXT_PERL_MODULE}.unit.so \\
+	install -p $NXT_BUILD_DIR/lib/unit/modules/${NXT_PERL_MODULE}.unit.so \\
 		\$(DESTDIR)$NXT_MODULESDIR/
 
 
diff --git a/auto/modules/php b/auto/modules/php
index 21dec215..a0f5379c 100644
--- a/auto/modules/php
+++ b/auto/modules/php
@@ -265,10 +265,10 @@ cat << END >> $NXT_MAKEFILE
 
 all: ${NXT_PHP_MODULE}
 
-${NXT_PHP_MODULE}:	$NXT_BUILD_DIR/${NXT_PHP_MODULE}.unit.so
+${NXT_PHP_MODULE}:	$NXT_BUILD_DIR/lib/unit/modules/${NXT_PHP_MODULE}.unit.so
 
-$NXT_BUILD_DIR/${NXT_PHP_MODULE}.unit.so:	$nxt_objs
-	\$(NXT_MODULE_LINK) -o $NXT_BUILD_DIR/${NXT_PHP_MODULE}.unit.so \\
+$NXT_BUILD_DIR/lib/unit/modules/${NXT_PHP_MODULE}.unit.so:	$nxt_objs
+	\$(NXT_MODULE_LINK) -o \$@ \\
 	$nxt_objs ${NXT_PHP_LIB} ${NXT_PHP_LDFLAGS} $NXT_LD_OPT
 
 
@@ -276,7 +276,7 @@ install: ${NXT_PHP_MODULE}-install
 
 ${NXT_PHP_MODULE}-install: ${NXT_PHP_MODULE} install-check
 	install -d \$(DESTDIR)$NXT_MODULESDIR
-	install -p $NXT_BUILD_DIR/${NXT_PHP_MODULE}.unit.so \\
+	install -p $NXT_BUILD_DIR/lib/unit/modules/${NXT_PHP_MODULE}.unit.so \\
 		\$(DESTDIR)$NXT_MODULESDIR/
 
 
diff --git a/auto/modules/python b/auto/modules/python
index d7504fc8..dfd632a1 100644
--- a/auto/modules/python
+++ b/auto/modules/python
@@ -157,7 +157,7 @@ for p in sys.path:
 
 print("};\n\n")
 
-' > $NXT_BUILD_DIR/$NXT_PYTHON_MOUNTS_HEADER
+' > $NXT_BUILD_DIR/include/$NXT_PYTHON_MOUNTS_HEADER
 
 
 $echo " + Python module: ${NXT_PYTHON_MODULE}.unit.so"
@@ -213,10 +213,10 @@ cat << END >> $NXT_MAKEFILE
 
 all: ${NXT_PYTHON_MODULE}
 
-${NXT_PYTHON_MODULE}:	$NXT_BUILD_DIR/${NXT_PYTHON_MODULE}.unit.so
+${NXT_PYTHON_MODULE}:	$NXT_BUILD_DIR/lib/unit/modules/${NXT_PYTHON_MODULE}.unit.so
 
-$NXT_BUILD_DIR/${NXT_PYTHON_MODULE}.unit.so:	$nxt_objs
-	\$(NXT_MODULE_LINK) -o $NXT_BUILD_DIR/${NXT_PYTHON_MODULE}.unit.so \\
+$NXT_BUILD_DIR/lib/unit/modules/${NXT_PYTHON_MODULE}.unit.so:	$nxt_objs
+	\$(NXT_MODULE_LINK) -o \$@ \\
 	$nxt_objs $NXT_PYTHON_LIBS $NXT_PYTHON_LDFLAGS $NXT_LD_OPT
 
 
@@ -224,7 +224,7 @@ install: ${NXT_PYTHON_MODULE}-install
 
 ${NXT_PYTHON_MODULE}-install: ${NXT_PYTHON_MODULE} install-check
 	install -d \$(DESTDIR)$NXT_MODULESDIR
-	install -p $NXT_BUILD_DIR/${NXT_PYTHON_MODULE}.unit.so \\
+	install -p $NXT_BUILD_DIR/lib/unit/modules/${NXT_PYTHON_MODULE}.unit.so \\
 		\$(DESTDIR)$NXT_MODULESDIR/
 
 
diff --git a/auto/modules/ruby b/auto/modules/ruby
index 99f6b286..7a7c9bd3 100644
--- a/auto/modules/ruby
+++ b/auto/modules/ruby
@@ -176,7 +176,7 @@ fi
 
 
 NXT_RUBY_MOUNTS_HEADER=nxt_${NXT_RUBY_MODULE}_mounts.h
-NXT_RUBY_MOUNTS_PATH=$NXT_BUILD_DIR/$NXT_RUBY_MOUNTS_HEADER
+NXT_RUBY_MOUNTS_PATH=$NXT_BUILD_DIR/include/$NXT_RUBY_MOUNTS_HEADER
 
 cat << END > $NXT_RUBY_MOUNTS_PATH
 
@@ -234,7 +234,7 @@ $NXT_BUILD_DIR/$nxt_obj:	$nxt_src $NXT_VERSION_H
 	\$(CC) -c \$(CFLAGS) $NXT_RUBY_CFLAGS -DNXT_RUBY_MOUNTS_H=\"$NXT_RUBY_MOUNTS_HEADER\" \\
            \$(NXT_INCS) $NXT_RUBY_INCPATH \\
 	$nxt_dep_flags \\
-	-o $NXT_BUILD_DIR/$nxt_obj $nxt_src
+	-o \$@ $nxt_src
 	$nxt_dep_post
 
 -include $NXT_BUILD_DIR/$nxt_dep
@@ -251,18 +251,17 @@ cat << END >> $NXT_MAKEFILE
 
 all: ${NXT_RUBY_MODULE}
 
-${NXT_RUBY_MODULE}:	$NXT_BUILD_DIR/${NXT_RUBY_MODULE}.unit.so
+${NXT_RUBY_MODULE}:	$NXT_BUILD_DIR/lib/unit/modules/${NXT_RUBY_MODULE}.unit.so
 
-$NXT_BUILD_DIR/${NXT_RUBY_MODULE}.unit.so:	$nxt_objs
-	\$(NXT_MODULE_LINK) -o $NXT_BUILD_DIR/${NXT_RUBY_MODULE}.unit.so \\
-	$nxt_objs $NXT_RUBY_LIBS $NXT_LD_OPT
+$NXT_BUILD_DIR/lib/unit/modules/${NXT_RUBY_MODULE}.unit.so:	$nxt_objs
+	\$(NXT_MODULE_LINK) -o \$@ $nxt_objs $NXT_RUBY_LIBS $NXT_LD_OPT
 
 
 install: ${NXT_RUBY_MODULE}-install
 
 ${NXT_RUBY_MODULE}-install: ${NXT_RUBY_MODULE} install-check
 	install -d \$(DESTDIR)$NXT_MODULESDIR
-	install -p $NXT_BUILD_DIR/${NXT_RUBY_MODULE}.unit.so \\
+	install -p $NXT_BUILD_DIR/lib/unit/modules/${NXT_RUBY_MODULE}.unit.so \\
 		\$(DESTDIR)$NXT_MODULESDIR/