This requires functions without a prototype definition to be static.
This allows to detect dead code, export less symbols and put shared
functions in headers.
A few pedantic changes and unused variables (1-4), and genuine bugs (5,
6).
The reports with the corresponding files and lines numbers are as
follows.
1. backend/libinput/tablet_pad.c@31,44,57
"Allocator sizeof operand mismatch"
"Result of 'calloc' is converted to a pointer of type 'unsigned int',
which is incompatible with sizeof operand type 'int'"
2. types/tablet_v2/wlr_tablet_v2_pad.c@371
"Allocator sizeof operand mismatch"
"Result of 'calloc' is converted to a pointer of type 'uint32_t', which
is incompatible with sizeof operand type 'int'"
3. types/wlr_cursor.c@335
"Dead initialization"
"Value stored to 'dx'/'dy' during its initialization is never read"
4. rootston/xdg_shell.c@510
"Dead initialization"
"Value stored to 'desktop' during its initialization is never read"
5. types/tablet_v2/wlr_tablet_v2_pad.c@475
"Dereference of null pointer"
"Access to field 'strips' results in a dereference of a null pointer
(loaded from field 'current_client')"
The boolean logic was incorrect (c.f. the check in the following
function).
6. examples/idle.c@163,174,182
"Uninitialized argument value"
"1st function call argument is an uninitialized value"
If close_timeout != 0, but simulate_activity_timeout >= close_timeout,
the program would segfault at pthread_cancel(t1).
