[fractal] build: Place target in meson build dir

[Daniel Garcia Moreno <danigm src gnome org>]

commit 919037495f7954267bae922174971ddef46d4e8c
Author: Christopher Davis <brainblasted disroot org>
Date:   Mon Apr 22 01:54:26 2019 -0400

    build: Place target in meson build dir
    
    Instead of putting target/ and in the source
    directory, we can tell our cargo script to put both target
    and our cargo-home in meson's build directory. This means
    that when triggering a rebuild through meson via tooling
    like Builder, Fractal will actually rebuild.

 .gitlab-ci.yml              |  2 +-
 fractal-gtk/src/meson.build |  1 +
 scripts/cargo.sh            | 10 ++++++----
 3 files changed, 8 insertions(+), 5 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 72e5cfea..fac6a915 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -16,7 +16,7 @@ variables:
         key: "flatpak"
         paths:
           - .flatpak-builder/cache/
-          - target/
+          - _build/target/
           - target_docs/
           - target_test/
 
diff --git a/fractal-gtk/src/meson.build b/fractal-gtk/src/meson.build
index 2e3a82bf..d529fb9e 100644
--- a/fractal-gtk/src/meson.build
+++ b/fractal-gtk/src/meson.build
@@ -46,6 +46,7 @@ cargo_release = custom_target('cargo-build',
                         command: [cargo_script,
                                   '@SOURCE_ROOT@',
                                   '@OUTPUT@',
+                                  meson.build_root(),
                                   profile
                                  ])
 
diff --git a/scripts/cargo.sh b/scripts/cargo.sh
index 7d4051a1..a8c7763e 100755
--- a/scripts/cargo.sh
+++ b/scripts/cargo.sh
@@ -1,13 +1,15 @@
 #!/bin/sh
 
-export CARGO_HOME=$1/target/cargo-home
-export FRACTAL_PROFILE="$3"
+export OUTPUT="$2"
+export CARGO_TARGET_DIR="$3"/target
+export CARGO_HOME="$CARGO_TARGET_DIR"/cargo-home
+export FRACTAL_PROFILE="$4"
 
 if [ "$FRACTAL_PROFILE" = "Devel" ]
 then
     echo "DEBUG MODE"
-    cargo build --manifest-path $1/Cargo.toml -p fractal-gtk && cp $1/target/debug/fractal-gtk $2
+    cargo build --manifest-path $1/Cargo.toml -p fractal-gtk && cp "$CARGO_TARGET_DIR"/debug/fractal-gtk 
"$OUTPUT"
 else
     echo "RELEASE MODE"
-    cargo build --manifest-path $1/Cargo.toml --release -p fractal-gtk && cp $1/target/release/fractal-gtk $2
+    cargo build --manifest-path $1/Cargo.toml --release -p fractal-gtk && cp 
"$CARGO_TARGET_DIR"/release/fractal-gtk "$OUTPUT"
 fi