Libc6-dev in core18

I have a snap which is built from a C program.
Up until now I used base:core but I now wish to move to base:core18.
The snap builds successfully but when I run it I get a segmentation fault in one of the C lib shared object files.
I am building for amd64 and using multipass to build.

Here is the section of my snapcraft file:

# Build the executable from c source
plugin: make
source: src
- gcc
- libc6-dev

Here is the error message (from dmesg) I get when I install my snap:

[530947.437260] ZapHost[2624]: segfault at ffffffffcfca6290 ip 00007fb7b9c44f23 sp 00007ffc45b2d868 error 5 in[7fb7b9b94000+1e7000]
[530947.831219] ZapHost[2644]: segfault at ffffffff8dfbe290 ip 00007f01465b3f23 sp 00007ffc4b606c98 error 5 in[7f0146503000+1e7000]
[530948.310143] ZapHost[2669]: segfault at 2e3d1290 ip 00007f8cc0850f23 sp 00007ffc96b322f8 error 4 in[7f8cc07a0000+1e7000]
[530948.615000] ZapHost[2691]: segfault at ffffffffae8c6290 ip 00007fe1faa7cf23 sp 00007fffefa09db8 error 5 in[7fe1fa9cc000+1e7000]
[530949.473450] ZapHost[2730]: segfault at ffffffffa423d290 ip 00007fb5ad9a7f23 sp 00007ffd3c2aef58 error 5 in[7fb5ad8f7000+1e7000]

Am I including the correct build-packages for core18 on amd64?
Thanks for any advice.