machinefiles: Allow keys to be stored case insensitive

This is required to make the various keys in the [user options] section
work the same as they do in the meson_options.txt file, where we don't
have any rules about case sensitivity.

There is some risk here. Someone may be relying on this lower by default
behavior, and this could break their machine files.

Fixes #7731

2 files changed, 9 insertions, 0 deletions

diff --git a/docs/markdown/Machine-files.md b/docs/markdown/Machine-files.md
index 5ac66a8..ab450cc 100644
--- a/docs/markdown/Machine-files.md
+++ b/docs/markdown/Machine-files.md
@@ -5,6 +5,9 @@ documentation on the common values used by both, for the specific values of
 one or the other see the [cross compilation](Cross-compilation.md) and [native
 environments](Native-environments.md).
 
+*Changed in 0.56.0* Keys within sections are now case sensitive. This is
+*required to make project options work correctly.
+
 ## Data Types
 
 There are four basic data types in a machine file:
diff --git a/docs/markdown/snippets/machine-files-case-insensitve.md b/docs/markdown/snippets/machine-files-case-insensitve.md
new file mode 100644
index 0000000..cacd37c
--- /dev/null
+++ b/docs/markdown/snippets/machine-files-case-insensitve.md
@@ -0,0 +1,6 @@
+## Machine file keys are stored case sensitive
+
+Previous the keys were always lowered, which worked fine for the values that
+were allowed in the machine files. With the addition of per-project options
+we need to make these sensitive to case, as the options in meson_options.txt
+are sensitive to case already.