* Unbreak build on FreeBSD
```
In file included from src/core/Alloc.cpp:24:
/usr/include/malloc.h:3:2: error: "<malloc.h> has been replaced by <stdlib.h>"
^
src/core/Alloc.cpp:65:28: error: use of undeclared identifier 'malloc_usable_size'
::operator delete(ptr, malloc_usable_size(ptr));
^
2 errors generated.
```
Non-standard APIs like `malloc_usable_size()` [1] are defined in
`malloc_np.h` on FreeBSD, so use it instead of `malloc.h` there.
[1] https://man.freebsd.org/jemalloc(3)
* Allow Browser HostInstaller to work on FreeBSD and other OS's
* Drop custom GNUInstallDirs cmake module and use cmake's own module
It seems to be an outdated version and cmake generally provides it
itself, so there should be no need for keepassxc to provide its own
custom version.
On FreeBSD this fixes the issue that man pages were installed into
the wrong directory, i.e., `/usr/local/share/man` vs `/usr/local/man`
as per FreeBSD's current packaging policy.
Signed-off-by: Tobias Kortkamp <tobik@FreeBSD.org>
To reduce residual fragments of secret data in memory after
deallocation, this patch replaces the global delete operator with a
version that zeros out previously allocated memory. It makes use of
the new C++14 sized deallocation, but provides an unsized fallback
with platform-specific size deductions.
This change is only a minor mitigation and cannot protect against
buffer reallocations by the operating system or non-C++ libraries.
Thus, we still cannot guarantee all memory to be wiped after free.
As a further improvement, this patch uses libgcrypt and libsodium
to write long-lived master key component hashes into a secure
memory area and wipe it afterwards.
The patch also fixes compiler flags not being set properly on macOS.
