openpgp: Enable time_t overflow test on other 32-bit platforms.

on Debian GNU/Linux systems, time_t is 4 octets for i386 (rust calls
this platform target_arch "x86"), armel ("arm"), armhf ("arm"), and
mipsel ("mips").  I've pulled these arch names from platforms [0].

[0] https://github.com/RustSec/platforms-crate/blob/main/src/target/arch.rs

There are likely other platforms that have a 32-bit time_t (and indeed,
some variants of 32-bit platforms like musl may have a 64-bit time_t [1]),
so this gating mechanism still isn't quite right.  But it's an improvement
over the status quo of just gating on target_arch = "x86".

[1] https://musl.libc.org/time64.html

1 files changed, 2 insertions, 2 deletions

diff --git a/openpgp/src/types/timestamp.rs b/openpgp/src/types/timestamp.rs
index c253efbe..1d9c2b84 100644
--- a/openpgp/src/types/timestamp.rs
+++ b/openpgp/src/types/timestamp.rs
@@ -669,9 +669,9 @@ mod tests {
     }
 
     // #668
-    // Ensure that, on x86, Timestamps between i32::MAX + 1 and u32::MAX are
+    // Ensure that, on 32-bit platforms, Timestamps between i32::MAX + 1 and u32::MAX are
     // clamped down to i32::MAX, and values below are not altered.
-    #[cfg(target_arch = "x86")]
+    #[cfg(any(target_arch = "x86", target_arch = "arm", target_arch = "mips"))]
     #[test]
     fn system_time_32_bit() -> Result<()> {
         let t1 = Timestamp::from(u32::MAX);