Add support for target and prerequisite specific variable blocks

For example, now instead of:

lib{foo}: cxx.loptions += -static
lib{foo}: cxx.libs += -lpthread

We can write:

lib{foo}:
{
  cxx.loptions += -static
  cxx.libs += -lpthread
}

The same works for prerequisites as well as target type/patterns. For
example:

exe{*.test}:
{
  test = true
  install = false
}

5 files changed, 150 insertions, 3 deletions

diff --git a/tests/variable/prerequisite-specific/testscript b/tests/variable/prerequisite-specific/testscript
index ef14cfc..ed7c60b 100644
--- a/tests/variable/prerequisite-specific/testscript
+++ b/tests/variable/prerequisite-specific/testscript
@@ -62,6 +62,58 @@ EOI
   }
 EOE
 
+: block
+:
+$* <<EOI 2>>/~%EOE%
+foo = COX
+dir{x}: foo = FOX
+dir{x}: dir{a}:
+{
+  foo = FOO
+  bar = BAR
+}
+dump dir{x}
+EOI
+<stdin>:8:1: dump:
+%  .+/dir\{x/\}:%
+  {
+    foo = FOX
+  }
+%  .+/dir\{x/\}: .+:dir\{a/\}:%
+  {
+    bar = BAR
+    foo = FOO
+  }
+EOE
+
+: block-multiple
+:
+$* <<EOI 2>>/~%EOE%
+dir{y}: foo = FOX
+dir{x} dir{y}: dir{a} dir{b}:
+{
+  foo += FOO
+  bar = BAR $foo
+}
+dump dir{y}
+EOI
+<stdin>:7:1: dump:
+%  .+/dir\{y/\}:%
+  {
+    foo = FOX
+  }
+%  .+/dir\{y/\}: .+:dir\{a/\}:%
+  {
+    bar = BAR FOX FOO
+    foo = FOX FOO
+  }
+%  .+/dir\{y/\}: .+:dir\{b/\}:%
+  {
+    bar = BAR FOX FOO
+    foo = FOX FOO
+  }
+EOE
+
 : chain
 :
 $* <<EOI 2>>/~%EOE%
diff --git a/tests/variable/scope-specific/testscript b/tests/variable/scope-specific/testscript
index 5f9a05d..13e7eca 100644
--- a/tests/variable/scope-specific/testscript
+++ b/tests/variable/scope-specific/testscript
@@ -42,7 +42,7 @@ EOO
 $* <<EOI 2>>EOE != 0
 foo/ [uint64] y
 EOI
-<stdin>:1:16: error: variable assignment expected instead of <newline>
+<stdin>:1:16: error: expected variable assignment instead of <newline>
 EOE
 
 : unexpected-attribute
diff --git a/tests/variable/target-specific/testscript b/tests/variable/target-specific/testscript
index 497c863..8b0a846 100644
--- a/tests/variable/target-specific/testscript
+++ b/tests/variable/target-specific/testscript
@@ -1,10 +1,10 @@
-# file      : tests/variable/scope-specific/testscript
+# file      : tests/variable/target-specific/testscript
 # copyright : Copyright (c) 2014-2018 Code Synthesis Ltd
 # license   : MIT; see accompanying LICENSE file
 
 .include ../../common.testscript
 
-: basic-line
+: basic
 :
 $* <<EOI >>EOO
 x = x
@@ -25,6 +25,38 @@ X
 Z
 EOO
 
+: block
+:
+$* <<EOI >>EOO
+x = x
+./:
+{
+  x = X
+  y = $x
+}
+print $(./: x)
+print $(./: y)
+EOI
+X
+X
+EOO
+
+: block-multiple
+:
+$* <<EOI >>EOO
+x = x
+file{foo} file{bar}:
+{
+  x += X
+  y = $x
+}
+print $(file{foo}: y)
+print $(file{bar}: y)
+EOI
+x X
+x X
+EOO
+
 : eval-qual
 :
 $* <<EOI >>EOO
diff --git a/tests/variable/target-type-pattern-specific/buildfile b/tests/variable/target-type-pattern-specific/buildfile
new file mode 100644
index 0000000..efed550
--- /dev/null
+++ b/tests/variable/target-type-pattern-specific/buildfile
@@ -0,0 +1,5 @@
+# file      : tests/variable/target-type-pattern-specific/buildfile
+# copyright : Copyright (c) 2014-2018 Code Synthesis Ltd
+# license   : MIT; see accompanying LICENSE file
+
+./: testscript $b
diff --git a/tests/variable/target-type-pattern-specific/testscript b/tests/variable/target-type-pattern-specific/testscript
new file mode 100644
index 0000000..e60dbe1
--- /dev/null
+++ b/tests/variable/target-type-pattern-specific/testscript
@@ -0,0 +1,58 @@
+# file      : tests/variable/target-type-pattern-specific/testscript
+# copyright : Copyright (c) 2014-2018 Code Synthesis Ltd
+# license   : MIT; see accompanying LICENSE file
+
+# NOTE: see also old tests.
+
+.include ../../common.testscript
+
+: basic
+:
+$* <<EOI >>EOO
+x = x
+y = y
+dir{*}: x  = X
+dir{*}: y += Y
+print $(./: x)
+print $(./: y)
+EOI
+X
+y Y
+EOO
+
+: block
+:
+$* <<EOI >>EOO
+x = x
+y = y
+dir{*}:
+{
+  x  = X
+  y += Y
+  z  = $x # Note: from scope.
+}
+print $(./: x)
+print $(./: y)
+print $(./: z)
+EOI
+X
+y Y
+x
+EOO
+
+: block-multiple
+:
+$* <<EOI >>EOO
+x = x
+y = y
+file{f*} file{b*}:
+{
+  x  = X
+  y += Y
+}
+print $(file{foo}: x)
+print $(file{bar}: y)
+EOI
+X
+y Y
+EOO